Sticky event handling fixes

Fall back to publishing on a remote SFU if possible

.eslintrc.cjs

@@ -1,116 +0,0 @@
-const COPYRIGHT_HEADER = `/*
-Copyright %%CURRENT_YEAR%% New Vector Ltd.
-
-SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
-Please see LICENSE in the repository root for full details.
-*/
-
-`;
-
-module.exports = {
-  plugins: ["matrix-org", "rxjs", "jsdoc"],
-  extends: [
-    "plugin:matrix-org/react",
-    "plugin:matrix-org/a11y",
-    "plugin:matrix-org/typescript",
-    "prettier",
-    "plugin:rxjs/recommended",
-    "plugin:storybook/recommended",
-  ],
-  parserOptions: {
-    ecmaVersion: "latest",
-    sourceType: "module",
-    project: ["./tsconfig.json"],
-  },
-  env: {
-    browser: true,
-    node: true,
-  },
-  rules: {
-    "jsdoc/no-types": "error",
-    "jsdoc/empty-tags": "error",
-    "jsdoc/check-property-names": "error",
-    "jsdoc/check-values": "error",
-    "jsdoc/check-param-names": "warn",
-    // "jsdoc/require-param": "warn",
-    "jsdoc/require-param-description": "warn",
-    "matrix-org/require-copyright-header": ["error", COPYRIGHT_HEADER],
-    "jsx-a11y/media-has-caption": "off",
-    "react/display-name": "error",
-    // Encourage proper usage of Promises:
-    "@typescript-eslint/no-floating-promises": "error",
-    "@typescript-eslint/no-misused-promises": "error",
-    "@typescript-eslint/promise-function-async": "error",
-    "@typescript-eslint/require-await": "error",
-    "@typescript-eslint/await-thenable": "error",
-    // To help ensure that we get proper vite/rollup lazy loading (e.g. for matrix-js-sdk):
-    "@typescript-eslint/consistent-type-imports": [
-      "error",
-      { fixStyle: "inline-type-imports" },
-    ],
-    // To encourage good usage of RxJS:
-    "rxjs/no-exposed-subjects": "error",
-    "rxjs/finnish": ["error", { names: { "^this$": false } }],
-    "no-restricted-imports": [
-      "error",
-      {
-        paths: ["matrix-widget-api", "matrix-js-sdk"].flatMap((lib) =>
-          ["src", "src/", "src/index", "lib", "lib/", "lib/index"]
-            .map((path) => `${lib}/${path}`)
-            .map((name) => ({ name, message: `Please use ${lib} instead` })),
-        ),
-        patterns: [
-          ...["matrix-widget-api"].map((lib) => ({
-            group: ["src", "src/", "src/**", "lib", "lib/", "lib/**"].map(
-              (path) => `${lib}/${path}`,
-            ),
-            message: `Please use ${lib} instead`,
-          })),
-          // XXX: We use /lib in lots of places, so allow for now.
-          ...["matrix-js-sdk"].map((lib) => ({
-            group: ["src", "src/", "src/**"].map((path) => `${lib}/${path}`),
-            message: `Please use ${lib} instead`,
-          })),
-        ],
-      },
-    ],
-  },
-  overrides: [
-    {
-      files: ["src/*/**"],
-      rules: {
-        // In application code we should use the js-sdk logger, never console directly.
-        "no-console": ["error"],
-      },
-    },
-    {
-      files: [
-        "**/*.test.ts",
-        "**/*.test.tsx",
-        "**/test.ts",
-        "**/test.tsx",
-        "**/test-**",
-      ],
-      rules: {
-        "jsdoc/no-types": "off",
-        "jsdoc/empty-tags": "off",
-        "jsdoc/check-property-names": "off",
-        "jsdoc/check-values": "off",
-        "jsdoc/check-param-names": "off",
-        "jsdoc/require-param-description": "off",
-      },
-    },
-    {
-      files: ["playwright/**"],
-      rules: {
-        // Playwright as a `use` function that has nothing to do with React hooks.
-        "react-hooks/rules-of-hooks": "off",
-      },
-    },
-  ],
-  settings: {
-    react: {
-      version: "detect",
-    },
-  },
-};

.github/PULL_REQUEST_TEMPLATE.md

@@ -5,7 +5,7 @@
 > Every PR must have a linked issue
 > that a maintainer has reviewed and approved **before you started writing code**.
 > PRs that don't meet this requirement will not be reviewed.
-> See [CONTRIBUTING.md](https://github.com/element-hq/element-call/blob/livekit/CONTRIBUTING.md) for ElementCall decided for this approach.
+> See [CONTRIBUTING.md](https://github.com/element-hq/element-call/blob/main/CONTRIBUTING.md) for ElementCall decided for this approach.
 
 ## Content
 
@@ -39,7 +39,7 @@ Uncomment the markdown table below and fill in the last line:
 ## Checklist
 
 - [ ] A linked, pre-approved issue exists for this feature or UI change.
-- [ ] I have read [CONTRIBUTING.md](https://github.com/element-hq/element-call/blob/livekit/CONTRIBUTING.md) in full.
+- [ ] I have read [CONTRIBUTING.md](https://github.com/element-hq/element-call/blob/main/CONTRIBUTING.md) in full.
 - [ ] Pull request includes screenshots or videos for any UI changes.
 - [ ] Tests written for new code (and existing touched code where feasible).
 - [ ] Linter and other CI checks pass.

.github/labels.yml

@@ -0,0 +1,256 @@
+- name: "A-1:1"
+  description: "Calls between two people"
+  color: "bfd4f2"
+- name: "A-Big-Grid"
+  description: "The freedom layout system used for >12 participants"
+  color: "bfd4f2"
+- name: "A-Developer-Experience"
+  description: "Workflow of developing: building, linting, debugging, profiling, etc."
+  color: "c5def5"
+- name: "A-E2EE"
+  description: "End-to-end encryption"
+  color: "bfd4f2"
+- name: "A-Embedded"
+  description: "Using the app embedded within other Matrix clients (as a widget)"
+  color: "bfd4f2"
+- name: "A-Feedback-Reporting"
+  description: "Reporting process for bugs, debug logs (rageshakes), suggestions"
+  color: "bfd4f2"
+- name: "A-Freedom"
+  description: "Freedom layout, where participants can be rearranged and resized"
+  color: "bfd4f2"
+- name: "A-Handset"
+  description: "Audio playback through the earpiece of a phone. Also known as 'earpiece mode' or 'handset mode'."
+  color: "bfd4f2"
+- name: "A-Huddle"
+  description: "Ad-hoc calls in a room notifying others"
+  color: "bfd4f2"
+- name: "A-Lobby"
+  description: "The page before joining a call"
+  color: "bfd4f2"
+- name: "A-Login"
+  color: "bfd4f2"
+- name: "A-Matrix2.0"
+  description: "Issues relating to the Matrix 2.0 / MSC4143 work, such as sticky events and multi-sfu"
+  color: "bfd4f2"
+- name: "A-Media-Devices"
+  color: "BFD4F2"
+- name: "A-Media-Quality"
+  description: "Distortions or glitches in audio/video"
+  color: "bfd4f2"
+- name: "A-Meeting"
+  description: "Scheduled call on the calendar"
+  color: "bfd4f2"
+- name: "A-Mobile"
+  description: "Using the app on a mobile device"
+  color: "bfd4f2"
+- name: "A-Moderation"
+  description: "Access to calls and powers within calls"
+  color: "bfd4f2"
+- name: "A-Performance"
+  color: "bfd4f2"
+- name: "A-Reactions"
+  color: "bfd4f2"
+- name: "A-Registration"
+  color: "bfd4f2"
+- name: "A-Screen-Sharing"
+  color: "bfd4f2"
+- name: "A-SDK"
+  description: "SDK for building MatrixRTC + LiveKit widgets"
+  color: "c5def5"
+- name: "A-Settings"
+  color: "bfd4f2"
+- name: "A-SFU"
+  description: "Routing calls through a selective forwarding unit"
+  color: "bfd4f2"
+- name: "A-Signaling"
+  description: "Call signaling"
+  color: "bfd4f2"
+- name: "A-Simulcast"
+  description: "Automatic selection of variable video resolutions"
+  color: "bfd4f2"
+- name: "A-SPA"
+  description: "Standalone application accessed via call links"
+  color: "bfd4f2"
+- name: "A-Spatial-Audio"
+  description: "Directional audio based on where a speaker appears on screen"
+  color: "bfd4f2"
+- name: "A-Speech-Enhancement"
+  description: "Techniques to enhance the intelligibility of speech in calls"
+  color: "c5def5"
+- name: "A-Split-Grid"
+  description: "The freedom layout system used for ≤12 participants"
+  color: "bfd4f2"
+- name: "A-Spotlight"
+  description: "Spotlight layout, where the active speaker is foregrounded"
+  color: "bfd4f2"
+- name: "A-Telemetry-Posthog"
+  description: "Share opt in usage data for optimizing the app via posthog"
+  color: "bfd4f2"
+- name: "A-Testing"
+  description: "Integration tests, unit tests, etc."
+  color: "bfd4f2"
+- name: "A-Video-Rooms"
+  description: "Rooms reserved exclusively for calling"
+  color: "bfd4f2"
+- name: "A-Walkie-Talkie"
+  description: "Walkie-talkie / PTT (push-to-talk) mode"
+  color: "bfd4f2"
+- name: "A11y"
+  description: "Accessibility"
+  color: "4ADEC0"
+- name: "backport-candidate"
+  description: "Something that is a candidate for backport to a particular release branch"
+  color: "0B8D85"
+- name: "Claude-Review"
+  description: "Request code review from Claude"
+  color: "e57157"
+- name: "customer-retainer"
+  color: "F44A5F"
+- name: "dependencies"
+  description: "Pull requests that update a dependency file"
+  color: "0366d6"
+- name: "development build"
+  description: "runs yarn build process in development mode"
+  color: "1d76db"
+- name: "Discord"
+  description: "Use case familiar to Discord users"
+  color: "3670d2"
+- name: "docker build"
+  description: "Creates a docker image for this PR"
+  color: "0e8a16"
+- name: "EPIC"
+  color: "5319E7"
+- name: "good first issue"
+  description: "Good for newcomers"
+  color: "7057ff"
+- name: "Help Wanted"
+  description: "Community contributions are welcome!"
+  color: "159818"
+- name: "I18n"
+  description: "Internationalisation"
+  color: "d4c5f9"
+- name: "O-Frequent"
+  description: "Affects or can be seen by most users regularly or impacts most users' first experience"
+  color: "0052CC"
+- name: "O-Occasional"
+  description: "Affects or can be seen by some users regularly or most users rarely"
+  color: "1D76DB"
+- name: "O-Uncommon"
+  description: "Most users are unlikely to come across this or unexpected workflow"
+  color: "C5DEF5"
+- name: "p1"
+  description: "Must fix/implement before this is usable as a product"
+  color: "D93F0B"
+- name: "p2"
+  description: "Should fix/implement, but not at the expense of p1s"
+  color: "FBCA04"
+- name: "p3"
+  description: "Could fix/implement when time allows"
+  color: "0E8A16"
+- name: "PR-Breaking-Change"
+  description: "A Pull request that changes EC in a way that is incompatible to the previous version."
+  color: "D93F0B"
+- name: "PR-Bug-Fix"
+  description: "Release note category. A PR that fixes a bug."
+  color: "C2E0C6"
+- name: "PR-Developer-Experience"
+  description: "Release note category. A PR that does not change EC but improves working with the repository."
+  color: "C2E0C6"
+- name: "PR-Documentation"
+  description: "Release note category. A PR that improves the documentation."
+  color: "C2E0C6"
+- name: "PR-Feature"
+  description: "Release note category. A PR that introduces a new user facing feature."
+  color: "C2E0C6"
+- name: "PR-Improvement"
+  description: "Release note category. A PR that improves EC's performance or stability."
+  color: "C2E0C6"
+- name: "PR-Task"
+  description: "Release note category. A PR that is hidden from release note."
+  color: "C2E0C6"
+- name: "Privacy"
+  color: "f41192"
+- name: "Roadmap"
+  color: "57457E"
+- name: "S-Critical"
+  description: "Prevents work, causes data loss and/or has no workaround"
+  color: "bd0026"
+- name: "S-Major"
+  description: "Severely degrades major functionality or product features, with no satisfactory workaround"
+  color: "fc4e2a"
+- name: "S-Minor"
+  description: "Impairs non-critical functionality or suitable workarounds exist"
+  color: "feb24c"
+- name: "S-Tolerable"
+  description: "Low/no impact on users"
+  color: "ffeda0"
+- name: "Security"
+  color: "b3e5fc"
+- name: "storybook build"
+  description: "Build and deploy the storybook frontend to netlify."
+  color: "45cd61"
+- name: "T-Defect"
+  description: "Something isn't working: bugs, crashes, hangs, vulnerabilities, or other reported problems"
+  color: "98e6ae"
+- name: "T-Enhancement"
+  description: "New features, changes in functionality, performance boosts, user-facing improvements"
+  color: "98e6ae"
+- name: "T-Other"
+  description: "Questions, user support, anything else"
+  color: "98e6ae"
+- name: "T-Task"
+  description: "Refactoring, enabling or disabling functionality, other engineering tasks"
+  color: "98e6ae"
+- name: "X-Blocked"
+  description: "Cannot be merged due to external dependencies"
+  color: "ff7979"
+- name: "X-Cannot-Reproduce"
+  description: "Needs reproduction steps"
+  color: "ff7979"
+- name: "X-Needs-Design"
+  description: "May require input from the design team"
+  color: "ff7979"
+- name: "X-Needs-Info"
+  description: "This issue is blocked awaiting information from the reporter"
+  color: "ff7979"
+- name: "X-Needs-Investigation"
+  color: "ff7979"
+- name: "X-Needs-Product"
+  description: "More input needed from the Product team"
+  color: "ff7979"
+- name: "X-Regression"
+  color: "ff7979"
+- name: "X-Release-Blocker"
+  color: "ff7979"
+- name: "X-Spec-Changes"
+  description: "May require spec changes"
+  color: "ff7979"
+- name: "X-Won't-Fix"
+  description: "This will not be worked on"
+  color: "ff7979"
+- name: "Z-Community-Testing"
+  description: "Issues found during the community testing sessions"
+  color: "efefef"
+- name: "Z-Could"
+  color: "ededed"
+- name: "Z-Design"
+  color: "ededed"
+- name: "Z-Flaky-Test"
+  color: "aaaaaa"
+- name: "Z-Media-Failure"
+  description: "Someone's audio or video isn't coming through"
+  color: "ededed"
+- name: "Z-Must"
+  color: "ededed"
+- name: "Z-Platform-Specific"
+  color: "ededed"
+- name: "Z-Power-Users"
+  color: "ededed"
+- name: "Z-ProductPolish"
+  color: "aaaaaa"
+- name: "Z-Should"
+  color: "ededed"
+- name: "Z-Splitbrain"
+  description: "Someone who should be on the call isn't showing up"
+  color: "ededed"

.github/workflows/build-element-call.yaml

@@ -44,7 +44,9 @@ jobs:
           node-version-file: ".node-version"
       - name: Install dependencies
         # ignore-pnpmfile should never be commited. Make CI crash if it happened (`pnpmfileChecksum` is present)
-        run: "pnpm install --frozen-lockfile --ignore-pnpmfile"
+        run: "scripts/layered.sh --ignore-pnpmfile"
+        env:
+          PR_HEAD_REPO_OWNER: ${{ github.event.pull_request.head.repo.owner.login }}
       - name: Build Element Call
         run: pnpm run build:"$PACKAGE":"$BUILD_MODE"
         env:
@@ -62,5 +64,6 @@ jobs:
         with:
           name: build-output-${{ inputs.package }}
           path: dist
+          if-no-files-found: error
           # We'll only use this in a triggered job, then we're done with it
           retention-days: 1

.github/workflows/build.yaml

@@ -6,7 +6,7 @@ on:
       - opened
       - labeled
   push:
-    branches: [livekit, full-mesh]
+    branches: [main]
 jobs:
   build_full_element_call:
     # Use the full package vite build
@@ -22,8 +22,8 @@ jobs:
       SENTRY_AUTH_TOKEN: ${{ secrets.SENTRY_AUTH_TOKEN }}
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
   deploy_develop:
-    # Deploy livekit branch to call.element.dev after build completes
-    if: github.ref == 'refs/heads/livekit'
+    # Deploy main branch to call.element.dev after build completes
+    if: github.ref == 'refs/heads/main'
     needs: build_full_element_call
     runs-on: ubuntu-latest
     steps:
@@ -43,8 +43,8 @@ jobs:
                 }
             })
   docker_for_develop:
-    # Build docker and publish docker for livekit branch after build completes
-    if: github.ref == 'refs/heads/livekit'
+    # Build docker and publish docker for main branch after build completes
+    if: github.ref == 'refs/heads/main'
     needs: build_full_element_call
     permissions:
       contents: write
@@ -73,7 +73,10 @@ jobs:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
 
   build_sdk_element_call:
-    # Use the embedded package vite build
+    # The 'sdk' package is the CallViewModel bundle that predates the sdk/
+    # package (build:sdk:production, sdk-target-based-on-call-view-model/), not
+    # the package itself. The name is shared with pr-deploy.yaml, which always
+    # runs from main, so it stays until the bundle's consumers have moved over.
     uses: ./.github/workflows/build-element-call.yaml
     with:
       package: sdk

.github/workflows/claude.yaml

@@ -0,0 +1,90 @@
+name: Claude
+on:
+  pull_request:
+    types: [labeled]
+
+permissions:
+  # The action exchanges the GitHub OIDC token for a short-lived Anthropic
+  # access token. GitHub API access goes through CLAUDE_GH_TOKEN instead.
+  id-token: write
+
+jobs:
+  review:
+    name: Review
+    # Only run on labelling and skip forks.
+    if: github.event.label.name == 'Claude-Review' && github.event.pull_request.head.repo.full_name == github.repository
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
+        with:
+          # The review looks at the individual commits, not just the combined diff
+          fetch-depth: 0
+          persist-credentials: false
+      - name: Review
+        uses: anthropics/claude-code-action@6fed3ca145920b639991cb756090506e1bcaf515 # v1.0.245
+        with:
+          anthropic_federation_rule_id: fdrl_01XQmWo4nka1ZTqZdsdeScyr
+          anthropic_organization_id: dfbc9a23-d636-4653-8970-035204ef60fa
+          anthropic_service_account_id: svac_018Ay5qaA7ZW8X7XsbdekqUM
+          anthropic_workspace_id: wrkspc_01Aw8LHjBS6fZysu9yqzYifW
+          # The token used here must grant read access to code, issues, and metadata as well as
+          # read and write access to pull requests.
+          github_token: ${{ secrets.CLAUDE_GH_TOKEN }}
+          use_sticky_comment: true
+          track_progress: true
+          prompt: |
+            Review this pull request under the following (and no further) angles:
+
+            1. Scope:
+
+               - Does the PR do one thing?
+               - Is the PR free of unrelated fixes and drive-by refactorings?
+               - If the PR is large, could it reasonably be split into smaller PRs
+                 that still deliver value?
+
+            2. Commits:
+               
+               - Is the work split into self-contained commits of reasonable size?
+               - Are the commits arranged in a sensible order?
+               - Have required refactorings been split out into separate commits?
+               - Is the history free of "wip", checkpoint and fixup-style commits
+                 which only correct an earlier commit in the same PR?
+
+            3. Code:
+
+               - Are the code changes functionally correct?
+               - Do the changes introduce new security vulnerabilities or metadata
+                 leaks?
+               - Is the new code performant enough?
+               - Don't check anything that is already validated via other GitHub
+                 workflows like linting, formatting or tests passing.
+
+            Read the commits themselves with `git log` and `git diff` against
+            the base branch of the PR.
+
+            Drop any findings that are outside the above review angles or that don't
+            require resolution. Grade the severity of each finding as either "🟡 low",
+            "🟠 medium" or "🔴 high". Devise at least one possible resolution for each
+            finding.
+
+            Report the graded findings and resolutions from the "Code" angle as inline
+            comments. Add a footer "_-- Finding from automated review_" to each inline
+            comment.
+
+            Finally, report your overall result as PR comment. Start your message with
+            "# Automated review". Then add one section per review angle with:
+
+            - A verdict of "✅ PASS" or "❌ NEEDS WORK"
+            - A bullet list summarizing the remaining non-inlined graded findings and
+              resolutions (as nested bullets).
+
+            Be brief and concise in all your communication. Do not mention what you have
+            not covered and don't bring up issues that have already been fixed.
+
+            Use Markdown links for anything that can be navigated to on GitHub such
+            as files, commits, issues, pull requests, workflow runs, etc.
+          claude_args: |
+            --model claude-fable-5-1
+            --allowedTools "mcp__github_inline_comment__create_inline_comment,Bash(git log:*),Bash(git diff:*),Bash(git show:*)"
+            --max-turns 50

.github/workflows/lint.yaml

@@ -1,14 +1,22 @@
 name: Lint, format & type check
 on:
   pull_request: {}
+  workflow_call:
+    inputs:
+      matrix-js-sdk-sha:
+        type: string
+        required: false
+        description: The matrix-js-sdk commit to build against instead of the locked one
 jobs:
-  prettier:
+  lint:
     name: Lint, format & type check
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
         uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
+          # Inside a called workflow, github.repository is the caller so we need to make sure to still check out the EC repo here.
+          repository: ${{ inputs.matrix-js-sdk-sha && 'element-hq/element-call' || github.repository }}
           persist-credentials: false
       - name: Enable Corepack
         run: corepack enable
@@ -19,13 +27,16 @@ jobs:
           node-version-file: ".node-version"
       - name: Install dependencies
         # ignore-pnpmfile should never be commited. Make CI crash if it happened (`pnpmfileChecksum` is present)
-        run: "pnpm install --frozen-lockfile --ignore-pnpmfile"
-      - name: Prettier
-        run: "pnpm run prettier:check"
+        run: "scripts/layered.sh --ignore-pnpmfile"
+        env:
+          PR_HEAD_REPO_OWNER: ${{ github.event.pull_request.head.repo.owner.login }}
+          JS_SDK_GITHUB_BASE_REF: ${{ inputs.matrix-js-sdk-sha }}
+      - name: Formatting
+        run: "pnpm run format:check"
       - name: i18n
         run: "pnpm run i18n:check"
-      - name: ESLint
-        run: "pnpm run lint:eslint"
+      - name: Lint
+        run: "pnpm run lint:oxlint"
       - name: Type check
         run: "pnpm run lint:types"
       - name: Dead code analysis

.github/workflows/publish-embedded-packages.yaml

@@ -9,7 +9,7 @@ on:
       - opened
       - labeled
   push:
-    branches: [livekit]
+    branches: [main]
 
 jobs:
   versioning:

.github/workflows/sync-labels.yml

@@ -0,0 +1,23 @@
+name: Sync labels
+on:
+  workflow_dispatch: {}
+
+  push:
+    branches:
+      - main
+    paths:
+      - .github/labels.yml
+      - .github/workflows/sync-labels.yml
+
+permissions: {} # We use LABEL_SYNC_GITHUB_TOKEN instead
+
+jobs:
+  sync-labels:
+    uses: element-hq/element-meta/.github/workflows/sync-labels.yml@7f2f93fb9b52ece7a0998f60e64862aa203c1746
+    with:
+      LABELS: |
+        .github/labels.yml
+      DELETE: true
+      WET: true
+    secrets:
+      ELEMENT_BOT_TOKEN: ${{ secrets.LABEL_SYNC_GITHUB_TOKEN }}

.github/workflows/test.yaml

@@ -2,19 +2,36 @@ name: Test
 on:
   pull_request: {}
   push:
-    branches: [livekit]
+    branches: [main]
+  workflow_call:
+    inputs:
+      matrix-js-sdk-sha:
+        type: string
+        required: false
+        description: The matrix-js-sdk commit to build against instead of the locked one
+      disable_coverage:
+        type: boolean
+        required: false
+        default: false
+        description: Skip generating and uploading coverage reports
+      disable_e2e_tests:
+        type: boolean
+        required: false
+        default: false
+        description: Skip the end-to-end tests
+    secrets:
+      CODECOV_TOKEN:
+        required: false
 jobs:
   vitest:
     name: Run unit tests
     runs-on: ubuntu-latest
-    container:
-      # Make sure to grab the latest version of the Playwright image
-      # https://playwright.dev/docs/docker#pull-the-image
-      image: mcr.microsoft.com/playwright:v1.60.0-noble
     steps:
       - name: Checkout code
         uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
+          # Inside a called workflow, github.repository is the caller so we need to make sure to still check out the EC repo here.
+          repository: ${{ inputs.matrix-js-sdk-sha && 'element-hq/element-call' || github.repository }}
           persist-credentials: false
       - name: Enable Corepack
         run: corepack enable
@@ -25,10 +42,28 @@ jobs:
           node-version-file: ".node-version"
       - name: Install dependencies
         # ignore-pnpmfile should never be commited. Make CI crash if it happened (`pnpmfileChecksum` is present)
-        run: "pnpm install --frozen-lockfile --ignore-pnpmfile"
+        run: "scripts/layered.sh --ignore-pnpmfile"
+        env:
+          PR_HEAD_REPO_OWNER: ${{ github.event.pull_request.head.repo.owner.login }}
+          JS_SDK_GITHUB_BASE_REF: ${{ inputs.matrix-js-sdk-sha }}
+      - name: Get Playwright version
+        run: echo "PLAYWRIGHT_VERSION=$(pnpm list @playwright/test --depth=0 --json | jq -r '.[0].devDependencies["@playwright/test"].version')" >> $GITHUB_ENV
+      - name: Cache Playwright binaries
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6
+        id: playwright-cache
+        with:
+          path: |
+            ~/.cache/ms-playwright
+          key: ${{ runner.os }}-playwright-${{ env.PLAYWRIGHT_VERSION }}
+      - name: Install Playwright binaries
+        if: steps.playwright-cache.outputs.cache-hit != 'true'
+        run: pnpm playwright install --with-deps
       - name: Vitest
-        run: "pnpm run test:coverage"
+        run: pnpm vitest --coverage.enabled="$ENABLE_COVERAGE"
+        env:
+          ENABLE_COVERAGE: ${{ !inputs.disable_coverage }}
       - name: Upload to codecov
+        if: ${{ !inputs.disable_coverage }}
         uses: codecov/codecov-action@fb8b3582c8e4def4969c97caa2f19720cb33a72f # v7
         env:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
@@ -37,11 +72,14 @@ jobs:
           fail_ci_if_error: true
   playwright:
     name: Run end-to-end tests
+    if: ${{ !inputs.disable_e2e_tests }}
     timeout-minutes: 60
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
+          # Inside a called workflow, github.repository is the caller so we need to make sure to still check out the EC repo here.
+          repository: ${{ inputs.matrix-js-sdk-sha && 'element-hq/element-call' || github.repository }}
           persist-credentials: false
       - name: Enable Corepack
         run: corepack enable
@@ -51,13 +89,26 @@ jobs:
           node-version-file: ".node-version"
       - name: Install dependencies
         # ignore-pnpmfile should never be commited. Make CI crash if it happened (`pnpmfileChecksum` is present)
-        run: pnpm install --frozen-lockfile --ignore-pnpmfile
-      - name: Install Playwright Browsers
-        run: pnpm exec playwright install --with-deps
+        run: scripts/layered.sh --ignore-pnpmfile
+        env:
+          PR_HEAD_REPO_OWNER: ${{ github.event.pull_request.head.repo.owner.login }}
+          JS_SDK_GITHUB_BASE_REF: ${{ inputs.matrix-js-sdk-sha }}
+      - name: Get Playwright version
+        run: echo "PLAYWRIGHT_VERSION=$(pnpm list @playwright/test --depth=0 --json | jq -r '.[0].devDependencies["@playwright/test"].version')" >> $GITHUB_ENV
+      - name: Cache Playwright binaries
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6
+        id: playwright-cache
+        with:
+          path: |
+            ~/.cache/ms-playwright
+          key: ${{ runner.os }}-playwright-${{ env.PLAYWRIGHT_VERSION }}
+      - name: Install Playwright binaries
+        if: steps.playwright-cache.outputs.cache-hit != 'true'
+        run: pnpm playwright install --with-deps
       - name: Run backend components
         run: |
-          docker compose -f playwright-backend-docker-compose.yml -f playwright-backend-docker-compose.override.yml pull
-          docker compose -f playwright-backend-docker-compose.yml -f playwright-backend-docker-compose.override.yml up -d
+          docker compose -f docker-compose-dev.yml -f docker-compose-playwright.yml pull
+          docker compose -f docker-compose-dev.yml -f docker-compose-playwright.yml up -d
           docker ps
       - name: Run Playwright tests
         env:

.github/workflows/translations-download.yaml

@@ -40,8 +40,13 @@ jobs:
       - name: Fix the owner of the downloaded files
         run: "sudo chown runner:docker -R locales"
 
-      - name: Prettier
-        run: pnpm prettier:format
+      # Localazy doesn't write file contents in the same order that i18next-cli's
+      # extractor uses. We re-run the extractor after downloading to fix the order.
+      - name: i18n
+        run: pnpm i18n
+
+      - name: Formatting
+        run: pnpm format
 
       - name: Create Pull Request
         id: cpr
@@ -53,7 +58,7 @@ jobs:
           title: Localazy Download
           commit-message: Translations updates
           labels: |
-            T-Task
+            PR-Task
 
       - name: Enable automerge
         run: gh pr merge --merge --auto "$PR_NUMBER"

.github/workflows/translations-upload.yaml

@@ -2,7 +2,7 @@ name: Upload translation files to Localazy
 on:
   push:
     branches:
-      - livekit
+      - main
     paths-ignore:
       - ".github/**"
 

.github/workflows/zizmor.yml

@@ -2,7 +2,7 @@ name: GitHub Actions Security Analysis with zizmor 🌈
 
 on:
   push:
-    branches: ["livekit", "full-mesh"]
+    branches: ["main", "full-mesh"]
   pull_request: {}
 
 permissions: {}
@@ -15,9 +15,9 @@ jobs:
       security-events: write # Required for upload-sarif (used by zizmor-action) to upload SARIF files.
     steps:
       - name: Checkout repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
         with:
           persist-credentials: false
 
       - name: Run zizmor 🌈
-        uses: zizmorcore/zizmor-action@b1d7e1fb5de872772f31590499237e7cce841e8e # v0.5.3
+        uses: zizmorcore/zizmor-action@192e21d79ab29983730a13d1382995c2307fbcaa # v0.5.7

.gitignore

@@ -10,6 +10,9 @@ public/config.json
 backend/synapse_tmp/*
 backend/synapse_tmp_othersite/*
 /coverage
+
+# Transient agent scratch files
+/agent-workspace/
 config.json
 
 # Yarn
@@ -38,3 +41,6 @@ yarn-error.log
 
 *storybook.log
 storybook-static
+
+# Nested checkout made by scripts/layered.sh
+/matrix-js-sdk/

.oxfmtrc.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "./node_modules/oxfmt/configuration_schema.json",
+  "printWidth": 80,
+  "sortPackageJson": false,
+  "ignorePatterns": ["pnpm-lock.yaml", "node_modules", "dist"]
+}

.oxlintrc.json

@@ -0,0 +1,166 @@
+{
+  "$schema": "./node_modules/oxlint/configuration_schema.json",
+  "plugins": [
+    "eslint",
+    "import",
+    "jsdoc",
+    "jsx-a11y",
+    "promise",
+    "react",
+    "typescript",
+    "unicorn",
+    "vitest"
+  ],
+  "jsPlugins": [
+    "eslint-plugin-storybook",
+    "eslint-plugin-element-call"
+    // TODO: Re-enable once oxlint supports lint rules that rely on TypeScript type-awareness.
+    // "eslint-plugin-rxjs"
+  ],
+  "categories": {
+    "correctness": "error",
+    "perf": "error"
+  },
+  "options": {
+    "denyWarnings": true,
+    "typeAware": true
+  },
+  "env": {
+    "builtin": true
+  },
+  "rules": {
+    "element-call/copyright-header": [
+      "error",
+      "/*\nCopyright %%CURRENT_YEAR%% Element Creations Ltd.\n\nSPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial\nPlease see LICENSE in the repository root for full details.\n*/\n\n"
+    ],
+    "element-call/no-observablescope-leak": "error",
+    "element-call/no-top-level-logger-get-child": "error",
+    "element-call/sdk-import-boundary": "error",
+    "jsdoc/empty-tags": "error",
+    "jsdoc/check-property-names": "error",
+    "jsdoc/require-param-description": "warn",
+    "react/display-name": "error",
+    // TODO: These React Compiler-based rules joined oxlint's correctness
+    // category in v1.81 and flag many pre-existing patterns, including hooks
+    // like useLatest/useInitial/useReactiveState that intentionally access
+    // refs during render. Re-evaluate them when adopting the React Compiler.
+    "react/immutability": "off",
+    "react/no-deriving-state-in-effects": "off",
+    "react/preserve-manual-memoization": "off",
+    "react/refs": "off",
+    "react/set-state-in-effect": "off",
+    "react/static-components": "off",
+    "react/use-memo": "off",
+    // TODO: Re-enable once oxlint supports lint rules that rely on TypeScript type-awareness.
+    // "rxjs/no-exposed-subjects": "error",
+    // "rxjs/finnish": [
+    //   "error",
+    //   {
+    //     "names": {
+    //       "^this$": false
+    //     }
+    //   }
+    // ],
+    "no-restricted-imports": [
+      "error",
+      {
+        "patterns": [
+          {
+            "group": [
+              "matrix-widget-api/src",
+              "matrix-widget-api/src/",
+              "matrix-widget-api/src/**",
+              "matrix-widget-api/lib",
+              "matrix-widget-api/lib/",
+              "matrix-widget-api/lib/**"
+            ],
+            "message": "Please use matrix-widget-api instead"
+          },
+          {
+            "group": [
+              "matrix-js-sdk/src",
+              "matrix-js-sdk/src/",
+              "matrix-js-sdk/src/**",
+              "matrix-js-sdk/lib",
+              "matrix-js-sdk/lib/",
+              "matrix-js-sdk/lib/index"
+            ],
+            "message": "Please use matrix-js-sdk instead"
+          }
+        ]
+      }
+    ],
+    "typescript/no-floating-promises": "error",
+    "typescript/no-misused-promises": "error",
+    "typescript/promise-function-async": "error",
+    "typescript/require-await": "error",
+    "typescript/await-thenable": "error",
+    // To help ensure that we get proper vite/rollup lazy loading (e.g. for matrix-js-sdk).
+    "typescript/consistent-type-imports": [
+      "error",
+      {
+        "fixStyle": "inline-type-imports"
+      }
+    ],
+    // TODO: These had to be disabled in the eslint -> oxlint migration. Would be nice to
+    // enable them in future or at least document why we're disabling them.
+    "eslint/no-await-in-loop": "off",
+    "eslint/no-unused-vars": ["error", { "args": "none" }],
+    "import/default": "off",
+    "jsdoc/check-tag-names": "off",
+    "jsx-a11y/prefer-tag-over-role": "off",
+    "promise/no-callback-in-promise": "off",
+    "react/jsx-key": "off",
+    "react/jsx-no-constructed-context-values": "off",
+    "react/no-array-index-key": "off",
+    "react/no-children-prop": "off",
+    "react/no-object-type-as-default-prop": "off",
+    "typescript/no-misused-spread": "off",
+    "typescript/no-useless-default-assignment": "off",
+    "typescript/restrict-template-expressions": "off",
+    "typescript/unbound-method": "off",
+    "vitest/expect-expect": "off",
+    "vitest/no-conditional-expect": "off",
+    "vitest/no-disabled-tests": "off",
+    "vitest/require-mock-type-parameters": "off",
+    "vitest/require-to-throw-message": "off"
+  },
+  "overrides": [
+    {
+      "files": ["src/*/**"],
+      "rules": {
+        // In application code we should use the js-sdk logger, never console directly.
+        "no-console": "error"
+      }
+    },
+    {
+      "files": [
+        "**/*.test.ts",
+        "**/*.test.tsx",
+        "**/test.ts",
+        "**/test.tsx",
+        "**/test-**"
+      ],
+      "rules": {
+        // Tests often initialize an ObservableScope in an outer scope in
+        // beforeEach, which is not actually a problem
+        "element-call/no-observablescope-leak": "off",
+        "jsdoc/empty-tags": "off",
+        "jsdoc/check-property-names": "off",
+        "jsdoc/require-param-description": "off",
+        "jsx-a11y/media-has-caption": "off"
+        // TODO: Enable once oxlint supports them.
+        // "jsdoc/check-values": "off",
+        // "jsdoc/check-param-names": "off",
+        // "jsdoc/no-types": "off",
+      }
+    },
+    {
+      "files": ["playwright/**"],
+      "rules": {
+        // Playwright as a `use` function that has nothing to do with React hooks.
+        "react-hooks/rules-of-hooks": "off"
+      }
+    }
+  ]
+}

.prettierignore

@@ -1,3 +0,0 @@
-pnpm-lock.yaml
-node_modules
-dist

.prettierrc.json

@@ -1 +0,0 @@
-{}

.storybook/preview.tsx

@@ -7,14 +7,16 @@ Please see LICENSE in the repository root for full details.
 
 import type { Preview } from "@storybook/react-vite";
 import { TooltipProvider } from "@vector-im/compound-web";
-import i18n from "i18next";
 import { logger } from "matrix-js-sdk/lib/logger";
 
 import EN from "../locales/en/app.json";
 import { initReactI18next } from "react-i18next";
+import { i18n } from "../src/utils/i18n";
 import "../src/index.css";
 
-// Bare-minimum i18n config
+// Bare-minimum i18n config.
+// Unlike the app, stories register the instance as react-i18next's default
+// rather than wrapping every story in an <I18nextProvider>.
 i18n
   .use(initReactI18next)
   .init({

AGENTS.md

@@ -0,0 +1,56 @@
+# AGENTS.md — Element Call
+
+MatrixRTC (MSC4143) + LiveKit video calling, shipped standalone, as a widget in
+Element Web and Element X, as embedded packages, and as a React component in a
+host's page. It is the MatrixRTC reference implementation.
+
+## Non-negotiables
+
+- Features and UI changes need a pre-approved issue. No issue, no review.
+- Exactly one `PR-*` label per PR. CI enforces it; it drives the changelog.
+- New behaviour ships with unit tests, a story if it renders, and an e2e spec if it
+  is user-facing. All three.
+- Reuse an existing component. If you genuinely cannot, say so in the PR body and
+  name what you rejected — never add a new one silently.
+- Nothing reads the page. No `window.location`, `document.body`, `window.inner*`,
+  `@media`, global `i18next` or the `widget` global — take it from a provider.
+- The change works standalone, as a widget and as a component. Say what you checked.
+- Every gate below is green before you push.
+- Hand off after the first implementation, before the quality pass. Then commit on
+  the user's word where the setup allows it, or hand them the message.
+
+## Read before you
+
+| …                                | …                                                          |
+| -------------------------------- | ---------------------------------------------------------- |
+| start a task of any size         | [docs/agents/workflow.md](docs/agents/workflow.md)         |
+| touch call logic or a view model | [docs/agents/architecture.md](docs/agents/architecture.md) |
+| write any code                   | [docs/agents/code-style.md](docs/agents/code-style.md)     |
+| write a test, story or e2e spec  | [docs/agents/testing.md](docs/agents/testing.md)           |
+| open a PR                        | [CONTRIBUTING.md](CONTRIBUTING.md)                         |
+| implement from a feature spec    | [FEATURES_SPEC/AGENTS.md](FEATURES_SPEC/AGENTS.md)         |
+
+## Gates
+
+```sh
+pnpm lint            # tsc, oxlint, knip, component externals
+pnpm format          # oxfmt
+pnpm test            # vitest: unit and storybook projects
+pnpm i18n:check
+```
+
+`knip` fails on dead code; a file deliberately inert ahead of its consumer goes in
+`knip.ts` `ignoreFiles` with a reason.
+
+## A good PR
+
+- One slice, under ~400 changed lines, green on its own, linked to its issue.
+- View model + marble tests, thin view, a story per state, an e2e spec.
+- Any new shared component called out explicitly, with why nothing existing fit.
+- Template filled for real: what, why, before/after screenshots, repro steps.
+- Comments only where the code can't give the reason — see
+  [code-style.md](docs/agents/code-style.md#comments).
+- Anything that redraws continuously — an animation frame, a stream — says what it
+  costs, or better, counts the redraws in a test.
+- Branch `<handle>/<topic>`. Plain imperative commit subjects, no prefixes.
+- Once review starts, fix forward. Never force-push a regeneration over a review.

PR4331-merge.md

@@ -0,0 +1,232 @@
+# Merging PR #4331 onto the SDK / Element Call split
+
+How [element-hq/element-call#4331](https://github.com/element-hq/element-call/pull/4331)
+("LiveKit updates": MSC4195 client-server API tokens, `url` transports, delegation
+through the homeserver, a transport dev override) lands on `toger5/use-sdk`, where
+the MatrixRTC logic lives in `sdk/` and Element Call consumes it through
+`sdk/src/api.ts`. The PR was written against `main`, where all of this still sat
+in `src/state/CallViewModel/`. This document goes through the PR commit by commit,
+says whether each one lands in `sdk/` or `src/`, and how; the section
+[Changes to `api.ts`](#changes-to-apits) covers the public interface in full. The
+end state: this branch behaves exactly as the PR does, with the split and the
+`api.ts` seam intact.
+
+The PR's branch is checked out at `agent-workspace/pr4331-merge/worktree` for
+comparison. The `matrix-js-sdk` dependency is pinned to the same `develop`
+commit the PR uses (`4df2f2bf`, 43.0.0), which brings `UnstableLivekitTransport`,
+`CallMembership.backendIdentities`, `_unstable_getLivekitToken` and
+`_unstable_delegateDelayedLeave`. That bump also renamed
+`MatrixRTCSession.leaveRoomSession` to `leave`, which the SDK now calls.
+
+## Where each commit lands
+
+| #   | Commit                                                                    | Lands in      | How                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
+| --- | ------------------------------------------------------------------------- | ------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| 1   | Remove stray pause and improve logging for hung e2e tests                 | e2e           | Applied as is: `playwright.config.ts`, `playwright/widget/federated-call.test.ts`.                                                                                                                                                                                                                                                                                                                                                                                                |
+| 2   | Fix typo in the name of the createJWTToken Playwright fixture             | e2e           | Applied as is.                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
+| 3   | Advertise the loopback address from the dev LiveKit SFUs                  | backend       | Applied as is: `backend/dev_livekit*.yaml`.                                                                                                                                                                                                                                                                                                                                                                                                                                       |
+| 4   | Match LiveKit participants against all backend identities                 | sdk           | `RTCMember.backendIdentities` (new, see api.ts). `LivekitBackend.mediaFor` matches `member.backendIdentities.includes(p.identity)`; `RTCParticipation.data$` maps a packet's sender the same way. `mockRtcMembership` in both `sdk/src/utils/test.ts` and `src/utils/test.ts` takes the new 4-argument constructor and a `backendIdentities` override.                                                                                                                            |
+| 5   | Model ConnectionState as a discriminated union                            | sdk           | `Connection.ts` state is `{state: "initialized" \| "authenticating" \| "authenticated" (+ `livekitState`) \| "error" (+ `error`) \| "stopped"}`. Internal to the LiveKit backend: `connectionState.ts` maps it onto the backend-neutral `MediaConnectionState`, so nothing above the backend changes. `DataChannel.ts` and `ConnectionFactory.ts` follow.                                                                                                                         |
+| 6   | Show the whole transport in debug UI and logs                             | sdk + src     | SDK log lines use `JSON.stringify(transport)`. Element Call: `focusUrl$: Behavior<string>` on the member media view models becomes `transport$: Behavior<Transport>` (`TransportMetadata.raw`), carried through `GridTile`, `SpotlightTile`, `MediaView` to `RTCConnectionStats`, which prints the JSON. The old code showed `extractDomain(transport.id)`, which on this branch was already a JSON string, so this also fixes a latent bug.                                      |
+| 7   | Group livekitRoomItems$ by connection                                     | n/a           | `livekitRoomItems$` and `LivekitRoomAudioRenderer` do not exist on this branch: audio renders from `tracks$` (`MemberAudioRenderer`). Nothing to port.                                                                                                                                                                                                                                                                                                                            |
+| 8   | Move SFU authentication into livekit/auth and choose the endpoint by role | sdk           | `sdk/src/media-backend/livekit/auth/{index,openID,csApi,types}.ts` replace `openIDSFU.ts`. Publisher → legacy `/sfu/get`; subscriber → `/get_token`. `slotId` replaces the hard-coded `m.call#ROOM`: `MediaBackendContext.slotId`, taken from the js-sdk session in `RTCParticipation`. The `tokenEndpoint` option of `createLivekitBackend` and the derivation from `MatrixRTCMode` are gone.                                                                                    |
+| 9   | Let the publishing Connection authenticate itself                         | sdk           | Every `Connection` has a `role` and fetches its own token; `existingSFUConfig` is gone. `prepareLocalTransport` no longer fetches a token itself: it starts the publisher connection (through the connection map) and resolves once that connection reports `authenticated`, rejecting with its error otherwise. Since `LocalMembership` joins only after `preparedTransport$` resolves, the join waits for the publisher's token exactly as the PR's `authenticated$` gate does. |
+| 10  | Reduce ConnectionManager to a ConnectionMap                               | sdk           | `ConnectionMap.ts` replaces `ConnectionManager.ts`; `createConnectionMap$` takes a resolved local transport, and `LivekitBackend` wraps it in `mapScoped` over the local transport, as the PR's `CallViewModel` did. `LocalMedia.ts`, `DataChannel.ts` take `connectionMap$`.                                                                                                                                                                                                     |
+| 11  | Use the unstable LiveKit transport type                                   | sdk + src     | `UnstableLivekitTransport` / `isUnstableLivekitTransport` throughout the backend; `src/settings/settings.ts`, `DeveloperSettingsTab`, test helpers. Transport discovery in `sdk/src/matrixrtc/` is now backend neutral (filters by `type`, see commit 15).                                                                                                                                                                                                                        |
+| 12  | Identify transports by server name as well as URLs                        | sdk           | `TransportLocator {transport, serverName}` in `auth/types.ts`; `ConnectionMap.keyFor` keys on `(url, livekit_service_url, serverName)`. The server name is derived from the user id (`serverNameOf`) for remote members and from our own membership identity for the local transport, so neither `api.ts` nor the backend options need it.                                                                                                                                        |
+| 13  | Pin matrix-js-sdk to the member_id branch                                 | superseded    | By commit 19; the lockfile pins the PR's final `develop` commit.                                                                                                                                                                                                                                                                                                                                                                                                                  |
+| 14  | Get SFU tokens and delegate delayed leaves through the MSC4195 CS API     | sdk           | `auth/csApi.ts` (`_unstable_getLivekitToken`, `_unstable_delegateDelayedLeave`), `auth/index.ts` facade with the fallback rules. `LivekitBackend.delegateDelayedLeave` goes through the facade; the delegation probe asks only the service the publisher flow uses. `LivekitBackendOptions.client` picks the two new client methods.                                                                                                                                              |
+| 15  | Let developers override the whole transport                               | sdk + src     | `RTCParticipationOptions.transport` / `fallbackTransport` take a `Transport` instead of `transportUrl` / `fallbackTransportUrl` (see api.ts). Element Call: setting `custom-transport` (JSON) replaces `custom-livekit-url`; `DeveloperSettingsTab` edits JSON and validates through `authenticateWithTransport`; `InCallView` turns `config.livekit.livekit_service_url` into the fallback transport. Locale keys `developer_mode.custom_transport.*`.                           |
+| 16  | Deprecate the livekit.livekit_service_url config option                   | src           | Applied as is in `ConfigOptions.ts`.                                                                                                                                                                                                                                                                                                                                                                                                                                              |
+| 17  | Cover url transports end to end                                           | e2e + backend | `playwright/url-transport.spec.ts`, `backend/app-service*.yaml`, `docker-compose-dev.yml` (lk-jwt-service 0.8.0) copied as is.                                                                                                                                                                                                                                                                                                                                                    |
+| 18  | Retain compatibility in compatibility mode                                | superseded    | Reverted by commit 23 inside the PR; only its e2e spec edits survive, in the final spec file.                                                                                                                                                                                                                                                                                                                                                                                     |
+| 19  | Switch JS SDK back to develop                                             | deps          | `pnpm-lock.yaml` pins `4df2f2bf` and `matrix-widget-api` 1.20.0; `package.json` keeps `#develop`.                                                                                                                                                                                                                                                                                                                                                                                 |
+| 20  | Fall back to get_token as subscriber on widget API errors                 | sdk           | `isCsApiUnavailable` in `auth/index.ts`; `doNetworkOperationWithRetry(op, shouldRetry)` in `sdk/src/utils/network.ts` with `isNetworkError` in `csApi.ts`.                                                                                                                                                                                                                                                                                                                        |
+| 21  | Share a connection between homeservers using the same JWT service         | sdk           | `keyFor` ignores the server name for transports without a `url`; `removeDuplicateTransports` keeps the first locator so the local one wins.                                                                                                                                                                                                                                                                                                                                       |
+| 22  | Avoid null in transport dev setting                                       | src           | `transportText()` in `DeveloperSettingsTab.tsx`.                                                                                                                                                                                                                                                                                                                                                                                                                                  |
+| 23  | Make the auth choice mode independent again                               | sdk           | `chooseAuthFlow(transport, role)` has no mode parameter; `config.ts` documents that `MatrixRTCMode` decides how the membership is written, not how the transport is authenticated.                                                                                                                                                                                                                                                                                                |
+| 24  | Cover identity matching and delegation across transport shapes            | sdk + e2e     | Unit tests in `LivekitBackend.test.ts` (see below); `playwright/url-transport.spec.ts` final version.                                                                                                                                                                                                                                                                                                                                                                             |
+| 25  | Cover the subscriber token path, widget fallback and server names         | sdk + e2e     | `auth/openID.test.ts` subscriber cases; `playwright/widget/url-transport.test.ts`; the server-name test lives in `LivekitBackend.test.ts` ("connects to a remote member's transport on the member's homeserver").                                                                                                                                                                                                                                                                 |
+
+## Changes to `api.ts`
+
+Three changes to the public SDK interface, all forced by the PR's behaviour.
+
+### `RTCMember.backendIdentities` (new)
+
+```ts
+/** The membership's `rtcBackendIdentity`, `${userId}:${deviceId}`: a key and a debug label. */
+rtcBackendIdentity: string;
+/**
+ * Every identity the member may publish under on its transport: the
+ * participant identity the SFU sees, and the sender of its data packets.
+ * One per authentication flow the member's transport allows, so a transport
+ * with both a `url` and a `livekit_service_url` lists the hashed and the
+ * legacy identity, and the backend matches whichever shows up.
+ */
+backendIdentities: readonly string[];
+```
+
+Commit 4 of the PR. A member on a transport that carries both a `url` and a
+`livekit_service_url` may have authenticated through either flow and so has
+two candidate identities; the js-sdk now lists them on the membership. The
+backend matches media and data packets against the list.
+`rtcBackendIdentity` stays as the stable per-membership key Element Call uses
+for tile ids and the debug overlay, and its doc says that it is no longer
+what the backend matches on. Read off the membership, like the single identity
+before it; the backend will derive both once the identity scheme is its own.
+
+### `RTCParticipationOptions.transport` / `fallbackTransport` replace the url options
+
+```ts
+/**
+ * Use this transport instead of asking the homeserver. Any shape the
+ * backend serves: for LiveKit a `url`, a `livekit_service_url` or both.
+ */
+transport?: Transport;
+/** Use this transport when the homeserver advertises none of the backend's type. */
+fallbackTransport?: Transport;
+```
+
+Commit 15 of the PR. The developer override has to carry a whole transport so
+that a `url`-only or combined shape can be tested against a homeserver that
+does not advertise one yet; a URL cannot say which shape it is. This also
+removes the one piece of LiveKit knowledge that sat outside the backend:
+`LocalTransport.ts` and `TransportAutoDiscovery.ts` no longer build a
+`{type: "livekit", livekit_service_url}` object and filter by `transportType`
+only, which `LocalTransport.ts` had marked as the moment to do this. The
+host turns its config URL into a transport (`InCallView.rtcParticipationOptions`).
+
+### `TransportMetadata` is unchanged, with one documented limit
+
+`TransportMetadata.id` is still the raw transport serialised with sorted keys.
+The LiveKit backend now keys its connections on the transport plus the server
+name where the transport has a `url` (commits 12 and 21), so two homeservers
+advertising the same `url` get two connections but one `TransportMetadata`.
+`connectedTransports$` deduplicates, and `resolved$` reports the first
+connection's resolution. This is diagnostics only; the media and data paths
+go through the backend's own keys. Extending `TransportMetadata` with the
+server name was left out to keep the type transport neutral; a developer panel
+that needs it can be given a `serverName` on `BackendConnection` later.
+
+### Related, outside `api.ts`
+
+- `media-backend/api.ts`: `MediaBackendContext.slotId` (commit 8). The
+  client-server API issues a token for a slot, so the backend needs it;
+  `RTCParticipation` reads it from the js-sdk session.
+- `sdk/index.ts`: `authenticateWithTransport` is now the auth facade's
+  `getSFUConfig({client, membership, transport, serverName, roomId, slotId, role, logger})`
+  (object parameter, whole transport, server name); `AuthenticateWithTransportParams`
+  is exported for it; `TokenEndpoint` is gone.
+- `createLivekitBackend` options: `tokenEndpoint` is gone; `client` now picks
+  `_unstable_getLivekitToken` and `_unstable_delegateDelayedLeave` as well.
+- `config.ts`: the `MatrixRTCMode` doc no longer claims the mode picks the
+  JWT endpoint (commit 23).
+
+## Behaviour, side by side
+
+| Behaviour                              | PR on `main`                                                                                | This branch                                                                                                                 |
+| -------------------------------------- | ------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- |
+| Endpoint choice                        | `chooseAuthFlow` in `src/livekit/auth`                                                      | Same function, `sdk/src/media-backend/livekit/auth/index.ts`                                                                |
+| Join waits for the publisher's token   | `authenticated$` gate in `LocalMember.ts`                                                   | `prepareLocalTransport` resolves on the publisher connection's `authenticated` state; `LocalMembership` joins after it      |
+| Delegation probe                       | The flow's service only, in `LocalMember.joinParams$`                                       | The flow's service only, in `prepareLocalTransport`                                                                         |
+| Delegation handover                    | `delegateDelayedLeave` facade from `LocalMember`                                            | Same facade from `LivekitBackend.delegateDelayedLeave`, with the delay timeout from the session timings instead of `Config` |
+| Transport keys and connection sharing  | `ConnectionMap.keyFor` on `TransportLocator`                                                | Same, moved                                                                                                                 |
+| Server names                           | `membershipsAndTransports$` from the user id; `getLocalTransport` from `client.getDomain()` | `serverNameOf(userId)` for members; our own membership identity's user id for the local transport                           |
+| Identity matching                      | `membership.backendIdentities.includes(p.identity)`                                         | `member.backendIdentities.includes(p.identity)` in `mediaFor` and for data packets                                          |
+| Dev transport override                 | `customTransport` setting → `getLocalTransport`                                             | `customTransport` setting → `RTCParticipationOptions.transport`                                                             |
+| Config fallback                        | `RtcTransportAutoDiscovery.tryConfigTransport`                                              | Host builds the transport, `RTCParticipationOptions.fallbackTransport`                                                      |
+| Error for a `url` host without MSC4195 | `NoMatrix2AuthorizationService` from the publisher connection                               | Same error, surfaced through `prepareLocalTransport` → `state$ failed` → `fromMatrixRTCError`                               |
+
+One deliberate difference: on `main` the publisher connection fetches its token
+on every (re)creation and nothing else does; here it is the same, since the
+up-front token fetch in `prepareLocalTransport` is gone. There is no second
+token request per join.
+
+## Where the PR's new tests went
+
+| PR test                                                                               | Here                                                                                                                                                                                                                                                                                                 |
+| ------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `src/livekit/auth/index.test.ts`                                                      | `sdk/src/media-backend/livekit/auth/index.test.ts`. Rewritten on the network layer (fetch-mock for the JWT service, mocked client methods) because a `vi.mock` of the sibling `openID` module does not reach the facade's own import under `sdk/`. Same cases, plus a table for `chooseAuthFlow`.    |
+| `src/livekit/auth/openID.test.ts`                                                     | `sdk/src/media-backend/livekit/auth/openID.test.ts`, replacing `openIDSFU.test.ts`                                                                                                                                                                                                                   |
+| `ConnectionMap.test.ts` (incl. commit 21's sharing tests)                             | `sdk/src/media-backend/livekit/ConnectionMap.test.ts`, replacing `ConnectionManager.test.ts`; plus a role-tagging test                                                                                                                                                                               |
+| `Connection.test.ts` changes                                                          | `sdk/src/media-backend/livekit/Connection.test.ts`; plus a publisher-through-the-JWT-service case                                                                                                                                                                                                    |
+| `LocalMember.test.ts` "joins session with %s delegation support" (by transport shape) | `LivekitBackend.test.ts` "prepares the local transport and asks %s about delegation", "waits for the publisher connection to hold its token before the join", "fails the preparation with the publisher connection's error", "delegates the leave through the flow that authenticated the publisher" |
+| `MatrixLivekitMembers.test.ts` two-candidate-identity tests                           | `LivekitBackend.test.ts` › `mediaFor`                                                                                                                                                                                                                                                                |
+| `SessionBehaviors.test.ts` server-name test                                           | `LivekitBackend.test.ts` "connects to a remote member's transport on the member's homeserver"                                                                                                                                                                                                        |
+| `LocalTransport.test.ts` / `RtcTransportAutoDiscovery.test.ts` changes                | `sdk/src/matrixrtc/TransportAutoDiscovery.test.ts` (fallback is a transport)                                                                                                                                                                                                                         |
+| `DeveloperSettingsTab.test.tsx` custom transport cases                                | `src/settings/DeveloperSettingsTab.test.tsx`, snapshot updated for the label                                                                                                                                                                                                                         |
+| `DataChannel`, `LivekitBackend` registry tests                                        | Adapted to the state union and `TransportLocator`                                                                                                                                                                                                                                                    |
+| `playwright/url-transport.spec.ts`, `playwright/widget/url-transport.test.ts`         | Copied as is: they drive the app, which behaves the same                                                                                                                                                                                                                                             |
+
+The PR's `CallViewModel.test.ts`, `CallViewModelTestUtils.ts`, `LocalMember.test.ts`
+(the rest) and `MatrixAudioRenderer.test.tsx` edits have no counterpart: those
+modules were replaced by the SDK before this merge.
+
+## One fix the e2e run forced
+
+The bumped js-sdk sets `rtcBackendIdentity` to the legacy `${userId}:${deviceId}`
+identity for every membership (it is deprecated there; the hashed one now only
+appears in `backendIdentities`). On this branch the call view model keyed its
+tiles by `[dup, mediaId, rtcBackendIdentity]`, so a device that rejoined after an
+improper leave, which has two memberships until the stale one expires, produced
+duplicate keys and crashed the host's page with `UNKNOWN_ERROR`
+(`spa-call-sticky.spec.ts`, "rejoin after improper leave"). The key is now the
+membership's own `memberId`, and `MemberAudioRenderer` and the SDK harness key
+by it too. The PR on `main` keyed by the participant object as well and did not
+hit this.
+
+## Coverage added on the package branch, and one bug it found
+
+The PR's tests mostly covered the auth layer; the SDK modules under them had
+little or none. Added on the package branch, which this branch is rebased onto:
+
+| Module                                       | Test                                                                                                                                                                                  |
+| -------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `media-backend/livekit/Publisher.ts`         | `Publisher.test.ts`: the cases from `main`'s `localMember/Publisher.test.ts` on a real `LocalParticipant` with faked device and signalling calls, plus publish, unpublish and destroy |
+| `media-backend/livekit/LocalMedia.ts`        | `LocalMedia.test.ts`: on a fake connection map; publish before and after the connection, republish on a new connection, mutes remembered, first publish error, output device          |
+| `RTCParticipation.ts`                        | `RTCParticipation.test.ts`: on a fake media backend; join options, state machine, publishing only while joined, delegation, member ids per mode, key replay, data sender check        |
+| `matrixrtc/LocalTransport.ts`                | `LocalTransport.test.ts`: override, homeserver, fallback, none                                                                                                                        |
+| `matrixrtc/joinJsSdkSession.ts`              | `joinJsSdkSession.test.ts`: the js-sdk join options, the retry budget, the intent and sticky events                                                                                   |
+| `media-backend/livekit/publishOptions.ts`    | `publishOptions.test.ts`                                                                                                                                                              |
+| `media-backend/livekit/ConnectionFactory.ts` | `ConnectionFactory.test.ts`: the room options from the requests and media quality (the cases from `main`'s `ECConnectionFactory.test.ts`), `resolved$`                                |
+| `LivekitBackend.ts` › `mediaFor`             | A member on another transport, a member changing transport, a member without one (from `main`'s `MatrixLivekitMembers.test.ts`)                                                       |
+
+`ConnectionFactory.test.ts` reads the options off the real LiveKit room the
+factory builds instead of mocking `livekit-client`: a `vi.mock` of the package
+reached the factory's import on the package branch but not on this one.
+
+The `LocalMedia` tests found a race in `ObservableScope.reconcile`: the loop was
+marked as running until the promise of its last run had settled, a few
+microtasks after it had last checked for new values, so a value arriving in
+that window (a connection appearing at just that moment) was never processed.
+Fixed in `[SDK] Keep a value that reaches reconcile as its loop winds down`,
+with a test that drives the window microtask by microtask. Element Call's
+`src/state/ObservableScope.ts` re-exports the SDK's class, so the fix applies
+to the app as well.
+
+## Checked
+
+- `pnpm lint` (tsc, oxlint, knip, externals), `pnpm format:check`, `pnpm i18n:check`.
+- `pnpm test`: 119 unit files, 950 tests; 4 storybook files, 45 tests (after the coverage above).
+- Playwright on Chromium against the local Playwright backend, one worker:
+  - `playwright/url-transport.spec.ts`: 10 of 10 pass, including delegation
+    through the homeserver and the JWT service, the subscriber fallback, the
+    publisher error and the federated token.
+  - `playwright/widget/url-transport.test.ts`: passes.
+  - The rest of `playwright/*.spec.ts`, `playwright/component`, `playwright/sdk`:
+    48 pass, 1 skipped, 1 fails (`reconnect.spec.ts`, which fails on `main`
+    locally too because the local JWT service is slower than the spec's wait).
+  - `playwright/widget`: 7 of 10 pass, including `federated-call`. `huddle-call`
+    fails before any call code runs (the Element Web develop image's room list no
+    longer matches the helper's "Open room" selector), and `screen-share` looks
+    for `video[data-lk-source="screen_share"]`, an attribute the LiveKit React
+    components set and the SDK's plain `<video>` elements do not: a failure of this
+    branch that predates the PR.
+  - Local environment work needed for that: the othersite JWT service and nginx
+    containers had to be recreated from the compose file, two stale containers held
+    port 16080, and the widget helper's hard-coded `https://localhost:3000` was
+    pointed at 3100 for the run only, since port 3000 is taken on this machine.
+- Standalone, widget and component all go through `InCallView.rtcParticipationOptions`
+  and the SDK, so the change is the same in all three modes; the widget-specific
+  fallback (a host without MSC4533) is in `isCsApiUnavailable`.

README.md

@@ -34,15 +34,16 @@ You can find the latest development version continuously deployed to
 ## ✨ Key Features
 
 ✅ **Decentralized & Federated** – No central authority; works across Matrix
-homeservers.  
-✅ **End-to-End Encrypted** – Secure and private calls.  
-✅ **Standalone & Widget Mode** – Use as an independent app or embed in Matrix
-clients.  
-✅ **WebRTC-based** – No additional software required.  
+homeservers.
+✅ **End-to-End Encrypted** – Secure and private calls.
+✅ **Standalone, Widget & Component Mode** – Use as an independent app, embed
+in Matrix clients as a widget, or (experimentally) mount it as a React component
+inside your own application.
+✅ **WebRTC-based** – No additional software required.
 ✅ **Scalable with LiveKit** – Supports large meetings via SFU
-([MSC4195: MatrixRTC using LiveKit backend](https://github.com/hughns/matrix-spec-proposals/blob/hughns/matrixrtc-livekit/proposals/4195-matrixrtc-livekit.md)).  
+([MSC4195: MatrixRTC using LiveKit backend](https://github.com/hughns/matrix-spec-proposals/blob/hughns/matrixrtc-livekit/proposals/4195-matrixrtc-livekit.md)).
 ✅ **Raise Hand** – Participants can signal when they want to speak, helping to
-organize the flow of the meeting.  
+organize the flow of the meeting.
 ✅ **Emoji Reactions** – Users can react with emojis 👍️ 🎉 👏 🤘, adding
 engagement and interactivity to the conversation.
 
@@ -90,7 +91,9 @@ and voice calls within Matrix rooms.
 
 Element Call offers two packaging options: one for standalone or widget
 deployment, and another for seamless widget-based integration into messenger
-apps. Below is an overview of each option.
+apps. A third, experimental option builds it as a React component library for
+applications that want to render a call inside their own page rather than in an
+iframe. Below is an overview of each option.
 
 **Full Package** – Supports both **Standalone** and **Widget** mode. It is
 hosted as a static web page and can be accessed via a URL when used as a widget.
@@ -107,6 +110,11 @@ recommended method for embedding Element Call.
   <img src="./docs/embedded_package.drawio.png" alt="Element Call Embedded Package">
 </p>
 
+**Component Package (experimental)** – A library build of Element Call as a
+React component, consumed as a dependency by a host application that already
+has a Matrix client. See
+[Element Call as a component](#element-call-as-a-component-experimental) below.
+
 For more details on the packages, see the
 [Embedded vs. Standalone Guide](./docs/embedded_standalone.md).
 
@@ -115,30 +123,33 @@ For more details on the packages, see the
 For operating and deploying Element Call on your own server, refer to the
 [**Self-Hosting Guide**](./docs/self_hosting.md).
 
-## 🧭 MatrixRTC Backend Discovery and Selection
+## MatrixRTC Transports
 
-For proper Element Call operation each site deployment needs a MatrixRTC backend
-setup as outlined in the [Self-Hosting Guide](./docs/self_hosting.md). A typical
-federated site deployment for three different sites A, B and C is depicted below.
+For proper operation of Element Call, each deployment needs to set up a
+MatrixRTC transport in the form of a LiveKit server as outlined in the
+[Self-Hosting Guide](./docs/self_hosting.md). A typical federated site
+deployment for three different sites A, B and C is depicted below.
 
 <p align="center">
   <img src="./docs/Federated_Setup.drawio.png" alt="Element Call federated setup">
 </p>
 
-### Backend Discovery
+### Transport Discovery
 
-The MatrixRTC backend (according to
-[MSC4143](https://github.com/matrix-org/matrix-spec-proposals/pull/4143)) is
-announced by the Matrix site's `.well-known/matrix/client` file and discovered
-via the `org.matrix.msc4143.rtc_foci` key, e.g.:
+Element Call discovers the available MatrixRTC transports (as defined by
+[MSC4519](https://github.com/matrix-org/matrix-spec-proposals/pull/4519)) by
+hitting the `GET /_matrix/client/unstable/org.matrix.msc4143/rtc/transports`
+endpoint of the Client-Server API. An example response:
 
 ```json
-"org.matrix.msc4143.rtc_foci": [
+{
+  "rtc_transports": [
     {
-        "type": "livekit",
-        "livekit_service_url": "https://matrix-rtc.example.com/livekit/jwt"
-    },
-]
+      "type": "livekit",
+      "livekit_service_url": "https://matrix-rtc.example.com/livekit/jwt"
+    }
+  ]
+}
 ```
 
 where the format for MatrixRTC using LiveKit backend is defined in
@@ -149,7 +160,7 @@ via `livekit_service_url`.
 
 ### Backend Selection
 
-- Each call participant proposes their discovered MatrixRTC backend from
+- Each call participant proposes their discovered MatrixRTC transport from
   `org.matrix.msc4143.rtc_foci` in their `org.matrix.msc3401.call.member` state event.
 - For the **LiveKit** MatrixRTC backend
   ([MSC4195](https://github.com/hughns/matrix-spec-proposals/blob/hughns/matrixrtc-livekit/proposals/4195-matrixrtc-livekit.md)),
@@ -210,9 +221,117 @@ See also:
 
 - [Developing with linked packages](./docs/linking.md)
 
+#### Element Call as a component (experimental)
+
+Element Call can also be embedded directly into another React application
+rather than being loaded in an iframe as a widget. `pnpm build:component`
+builds it as a library into `component/dist` (the bundle, its stylesheet and
+type declarations), and
+
+```sh
+pnpm dev:component
+```
+
+serves a harness on port 3001 that stands in for such an application: it signs
+in twice against the development backend and shows two calls side by side, in
+resizable boxes, with page furniture of its own around them. Use it to see how
+Element Call behaves when it does not own the page — the size it is given,
+whether it stays inside its container, and what it says to its host, which is
+logged along the bottom. The harness is served with the same development
+certificate as the app, so unless the development CA is trusted, the browser
+needs a certificate exception for `https://localhost:3001` as well (see the
+note under [Backend](#backend)). It reads the same `public/config.json` as
+`pnpm dev` if one exists, and runs with Element Call's defaults otherwise.
+
+The call lays itself out for the size of the element it is mounted in, not the
+window: a host that shrinks the container to a corner of its page gets the
+picture-in-picture layout, just as a host that shrank the whole iframe used to.
+The breakpoints in the stylesheets the component uses are
+`@container element-call` queries against its root element for the same reason;
+for the standalone app the root is the page, so they mean what the media queries
+they replaced did. (The standalone-only views, such as the home and login pages,
+still use plain media queries, since the component never shows them.)
+
+The component's stylesheet is confined to the element it is mounted in: the
+build rewrites every selector so that it matches only Element Call's root or
+what is inside it, with `html`, `body` and `:root` standing for that root (see
+`component/build/scopeStylesToRoot.ts`). A host's own page keeps its styles,
+and Element Call brings its own fonts and design tokens along.
+
+The component speaks every language the app does. English is bundled in; the
+other locales are split into chunks the host's bundler loads the first time
+they are needed. It starts in the browser's language, and follows the host's
+own language setting through the `language` prop (`supportedLanguages` lists
+the tags it accepts, and anything else falls back to its base language or to
+English). The `theme` prop works the same way and takes the same values as the
+widget's `theme` URL parameter: `light`, `dark`, `light-high-contrast` or
+`dark-high-contrast`. Both can change while a call is running without
+disturbing it.
+
+A host must call and await `initializeElementCall(config)` once before
+rendering the component: it loads the `Intl` polyfills, applies the
+deployment-wide `config.json`-style configuration and sets up translations.
+The component itself takes the host's `client` and the `roomId` to call in, an
+`intent` saying what the user asked for (which decides whether to show the
+lobby, ring, and so on), an optional `config` overriding what the intent
+implies, and an optional `hostBridge` through which Element Call tells the host
+that the user has joined or hung up, that it wants to stay on screen, and so
+on. The host makes its own requests (`join`, `hangUp`, `setDeviceMute`) through
+the handle exposed on `ref`. The full API is documented in the type declarations
+(`component/index.tsx` and `component/host.ts`).
+
+A few things differ from the widget on purpose: the component draws a solid
+background rather than a gradient unless told otherwise, never offers to edit
+the user's profile (the account is the host's), scopes its keyboard shortcuts to
+its own root element so that several instances can share a page, and only shows
+its own post-call and error screens when the host has not supplied a `close()`
+callback; with one, it asks the host to unmount it instead. The
+[global JS controls](./docs/controls.md) on `window` are unchanged and remain
+page-wide, so with several instances on one page they apply to all of them.
+
+The package is not published yet. A host installs it as a git dependency on the
+`component` directory of this repository,
+
+```json
+"@element-hq/element-call-component": "github:element-hq/element-call#main&path:/component"
+```
+
+whose `prepare` script runs the build on install. That build needs pnpm (via
+Corepack) on the host's machine, runs a full `pnpm install` of this repository,
+since it inherits the `--max-old-space-size` setting of
+the app build; the host's pnpm also has to allow it to run at all
+(`allowBuilds` in its `pnpm-workspace.yaml`). Note that `component/` is a pnpm
+project of its own for this reason, so pnpm commands run from inside that
+directory target it rather than the repository; run them from the repository
+root. The host imports the component from
+`@element-hq/element-call-component` and the stylesheet from
+`@element-hq/element-call-component/style.css`, and has to provide `react`,
+`react-dom`, `matrix-js-sdk`, `@vector-im/compound-web` and
+`@vector-im/compound-design-tokens` itself, since the bundle leaves them
+external.
+Compound's stylesheet are the host's to load too: the component shares
+the host's copy of Compound, (required for example for tooltips)
+
+The component is large, and a host will usually load it lazily, only once a
+call is shown. Everything a host needs in order to talk about a call before
+then is also exported
+from `@element-hq/element-call-component/api` (a small entry point that does not
+load the component).
+
+- props and the types they are made of
+- the handle
+- the host bridge
+- `UserIntent`
+- `HeaderStyle`
+- `BackgroundStyle` enums
+- `configurationForIntent`, the defaults each intent implies
+  Import from it wherever a value such as
+  `BackgroundStyle.Solid` is needed on a path that must stay light; the main
+  entry point re-exports all of it too.
+
 ### Backend
 
-A docker compose file `dev-backend-docker-compose.yml` is provided to start the
+A docker compose file `docker-compose-dev.yml` is provided to start the
 whole stack of components which is required for a local development environment
 including federation:
 
@@ -239,15 +358,14 @@ the backend components:
 ```sh
 pnpm backend
 # or for podman-compose:
-# podman-compose -f dev-backend-docker-compose.yml up
+# podman-compose -f docker-compose-dev.yml up
 ```
 
 > [!NOTE]
 > To ensure your local development frontend functions properly, you’ll need to
-> add certificate exceptions in your browser for `https://localhost:3000`,
-> `https://matrix-rtc.m.localhost/livekit/jwt/healthz` and
-> `https://synapse.m.localhost/.well-known/matrix/client`. This can be either
-> done by adding the minimum localhost CA
+> add certificate exceptions in your browser for `https://localhost:3000` and
+> `https://matrix-rtc.m.localhost/livekit/jwt/healthz`. This can be done either
+> by adding the minimum localhost CA
 > ([./backend/dev_tls_local-ca.crt](./backend/dev_tls_local-ca.crt)) to your web
 > browser's trusted certificates or by simply copying and pasting each URL into
 > your browser’s address bar and follow the prompts to add the exception.
@@ -272,7 +390,10 @@ running Playwright by following
 
 However the Playwright tests are run, an element-call instance must be running
 on https://localhost:3000 (this is configured in `playwright.config.ts`) - this
-is what will be tested.
+is what will be tested. The tests under `playwright/component` instead drive
+the component harness (`pnpm dev:component`) on https://localhost:3001, which
+Playwright starts as a second web server; it is always a Vite dev server, even
+when the app itself is served from Docker with `USE_DOCKER`.
 
 The local backend environment should be running for the test to work:
 `pnpm backend`
@@ -359,9 +480,19 @@ Usage and other technical details about the project can be found here:
 
 [**Docs**](./docs/README.md)
 
+## GitHub Labels
+
+GitHub labels in this repository are maintained in the [`labels.yml`](.github/labels.yml) file and
+automatically synced to GitHub using the [`sync-labels` workflow](.github/workflows/sync-labels.yml).
+We do this so that we can reuse the labels between repositories.
+
+> [!WARNING]
+> Do not manually edit labels in the GitHub UI. Any manual changes will be overridden by the
+> workflow on its next invocation.
+
 ## 📝 Copyright & License
 
-Copyright 2021-2025 New Vector Ltd
+Copyright 2021-2026 New Vector Ltd
 
 This software is dual-licensed by New Vector Ltd (Element). It can be used
 either:

babel.config.cjs

@@ -1,20 +0,0 @@
-module.exports = {
-  presets: [
-    [
-      "@babel/preset-env",
-      {
-        targets: {
-          node: "current",
-        },
-      },
-    ],
-    [
-      "@babel/preset-react",
-      {
-        runtime: "automatic",
-      },
-    ],
-    "@babel/preset-typescript",
-  ],
-  plugins: ["babel-plugin-transform-vite-meta-env"],
-};

backend/app-service-othersite.yaml

@@ -0,0 +1,17 @@
+id: "lk-jwt-service-othersite"
+as_token: "ec_dev_as_token_othersite_0123456789ab"
+hs_token: "ec_dev_hs_token_othersite_0123456789ab"
+sender_localpart: "_lk_jwt_service"
+namespaces:
+  users:
+    - exclusive: false
+      regex: "@.*:synapse\\.othersite\\.m\\.localhost" # Cover all local users
+# Required for Synapse to call POST /_matrix/app/v1/ping on this service.
+url: "http://auth-server-1:16080"
+# Enable membership look-ups via /is_joined.
+io.element.msc4502.scopes:
+  ["urn:matrix:client:io.element.msc4502:rooms:is_joined"]
+# Route /_matrix/client/(v*|unstable/*)/rtc/livekit/* C-S and S-S requests to this
+# service.
+io.element.msc4512.proxy_prefix: "rtc/livekit"
+io.element.msc4512.proxy_url: "http://auth-server-1:16080"

backend/app-service.yaml

@@ -0,0 +1,17 @@
+id: "lk-jwt-service"
+as_token: "ec_dev_as_token_main_0123456789ab"
+hs_token: "ec_dev_hs_token_main_0123456789ab"
+sender_localpart: "_lk_jwt_service"
+namespaces:
+  users:
+    - exclusive: false
+      regex: "@.*:synapse\\.m\\.localhost" # Cover all local users
+# Required for Synapse to call POST /_matrix/app/v1/ping on this service.
+url: "http://auth-server:6080"
+# Enable membership look-ups via /is_joined.
+io.element.msc4502.scopes:
+  ["urn:matrix:client:io.element.msc4502:rooms:is_joined"]
+# Route /_matrix/client/(v*|unstable/*)/rtc/livekit/* C-S and S-S requests to this
+# service.
+io.element.msc4512.proxy_prefix: "rtc/livekit"
+io.element.msc4512.proxy_url: "http://auth-server:6080"

backend/dev_homeserver-othersite.yaml

@@ -40,6 +40,15 @@ experimental_features:
   msc4222_enabled: true
   # sticky events for MatrixRTC user state
   msc4354_enabled: true
+  # MatrixRTC
+  msc4143_enabled: true
+  # Enable membership look-up via /is_joined.
+  msc4502_enabled: true
+  # Enable C-S & S-S request proxying for application services.
+  msc4512_enabled: true
+
+app_service_config_files:
+  - /data/cfg/app-service.yaml
 
 # The maximum allowed duration by which sent events can be delayed, as
 # per MSC4140. Must be a positive value if set.  Defaults to no
@@ -54,7 +63,6 @@ enable_registration_without_verification: true
 registration_shared_secret: "test_shared_secret_for_local_dev_only"
 
 report_stats: false
-serve_server_wellknown: true
 
 # Ratelimiting settings for client actions (registration, login, messaging).
 #
@@ -67,3 +75,8 @@ rc_message:
   # Currently the heart-beat is every 5 seconds which translates into a rate of 0.2s
   per_second: 0.5
   burst_count: 30
+
+matrix_rtc:
+  transports:
+    - type: livekit
+      livekit_service_url: https://matrix-rtc.othersite.m.localhost/livekit/jwt

backend/dev_homeserver.yaml

@@ -40,6 +40,15 @@ experimental_features:
   msc4222_enabled: true
   # sticky events for MatrixRTC user state
   msc4354_enabled: true
+  # MatrixRTC
+  msc4143_enabled: true
+  # Enable membership look-up via /is_joined.
+  msc4502_enabled: true
+  # Enable C-S & S-S request proxying for application services.
+  msc4512_enabled: true
+
+app_service_config_files:
+  - /data/cfg/app-service.yaml
 
 # The maximum allowed duration by which sent events can be delayed, as
 # per MSC4140. Must be a positive value if set.  Defaults to no
@@ -54,7 +63,6 @@ enable_registration_without_verification: true
 registration_shared_secret: "test_shared_secret_for_local_dev_only"
 
 report_stats: false
-serve_server_wellknown: true
 
 # Ratelimiting settings for client actions (registration, login, messaging).
 #
@@ -67,3 +75,8 @@ rc_message:
   # Currently the heart-beat is every 5 seconds which translates into a rate of 0.2s
   per_second: 0.5
   burst_count: 30
+
+matrix_rtc:
+  transports:
+    - type: livekit
+      livekit_service_url: https://matrix-rtc.m.localhost/livekit/jwt

backend/dev_livekit-othersite.yaml

@@ -6,6 +6,11 @@ rtc:
   port_range_start: 50300
   port_range_end: 50400
   use_external_ip: false
+  # Advertise the loopback address instead of the container IP, which is not
+  # routable from the host when Docker runs in a VM (colima, Docker Desktop).
+  # The browser then reaches the SFU through the published ports. Firefox
+  # ignores loopback candidates, so this only works in Chromium-based browsers.
+  node_ip: 127.0.0.1
 turn:
   enabled: false
   domain: localhost

backend/dev_livekit.yaml

@@ -6,6 +6,11 @@ rtc:
   port_range_start: 50100
   port_range_end: 50200
   use_external_ip: false
+  # Advertise the loopback address instead of the container IP, which is not
+  # routable from the host when Docker runs in a VM (colima, Docker Desktop).
+  # The browser then reaches the SFU through the published ports. Firefox
+  # ignores loopback candidates, so this only works in Chromium-based browsers.
+  node_ip: 127.0.0.1
 turn:
   enabled: false
   domain: localhost

backend/dev_nginx.conf

@@ -1,4 +1,4 @@
-# Synapse reverse proxy including .well-known/matrix/client
+# Synapse reverse proxy
 # domain synapse.m.localhost
 server {
     listen                  80;
@@ -11,18 +11,6 @@ server {
     ssl_certificate         /root/ssl/cert.pem;
     ssl_certificate_key     /root/ssl/key.pem;
 
-    # well-known config adding rtc_foci backend
-    # Note well-known is currently not effective due to:
-    # https://spec.matrix.org/v1.12/client-server-api/#well-known-uri the spec
-    # says it must be at https://$server_name/... (implied port 443) Hence, we
-    # currently rely for local development environment on deprecated config.json
-    # setting for livekit_service_url
-    location /.well-known/matrix/client {
-        add_header Access-Control-Allow-Origin *;
-        return 200 '{"m.homeserver": {"base_url": "https://synapse.m.localhost"}, "org.matrix.msc4143.rtc_foci": [{"type": "livekit", "livekit_service_url": "https://matrix-rtc.m.localhost/livekit/jwt"}]}';
-        default_type application/json;
-    }
-
     # Reverse proxy for Matrix Synapse Homeserver
     # This is also required for development environment.
     # Reason: the lk-jwt-service uses the federation API for the openid token
@@ -44,7 +32,7 @@ server {
 
 }
 
-# Synapse reverse proxy including .well-known/matrix/client
+# Synapse reverse proxy
 # domain synapse.othersite.m.localhost
 server {
     listen                  80;
@@ -57,18 +45,6 @@ server {
     ssl_certificate         /root/ssl/cert.pem;
     ssl_certificate_key     /root/ssl/key.pem;
 
-    # well-known config adding rtc_foci backend
-    # Note well-known is currently not effective due to:
-    # https://spec.matrix.org/v1.12/client-server-api/#well-known-uri the spec
-    # says it must be at https://$server_name/... (implied port 443) Hence, we
-    # currently rely for local development environment on deprecated config.json
-    # setting for livekit_service_url
-    location /.well-known/matrix/client {
-        add_header Access-Control-Allow-Origin *;
-        return 200 '{"m.homeserver": {"base_url": "https://synapse.othersite.m.localhost"}, "org.matrix.msc4143.rtc_foci": [{"type": "livekit", "livekit_service_url": "https://matrix-rtc.othersite.m.localhost/livekit/jwt"}]}';
-        default_type application/json;
-    }
-
     # Reverse proxy for Matrix Synapse Homeserver
     # This is also required for development environment.
     # Reason: the lk-jwt-service uses the federation API for the openid token

backend/playwright_homeserver-othersite.yaml

@@ -40,6 +40,15 @@ experimental_features:
   msc4222_enabled: true
   # sticky events for MatrixRTC user state
   msc4354_enabled: true
+  # MatrixRTC
+  msc4143_enabled: true
+  # Enable membership look-up via /is_joined.
+  msc4502_enabled: true
+  # Enable C-S & S-S request proxying for application services.
+  msc4512_enabled: true
+
+app_service_config_files:
+  - /data/cfg/app-service.yaml
 
 # The maximum allowed duration by which sent events can be delayed, as
 # per MSC4140. Must be a positive value if set.  Defaults to no
@@ -54,7 +63,6 @@ enable_registration_without_verification: true
 registration_shared_secret: "test_shared_secret_for_local_dev_only"
 
 report_stats: false
-serve_server_wellknown: true
 
 # Ratelimiting settings for client actions (registration, login, messaging).
 #
@@ -84,3 +92,8 @@ rc_login:
 rc_registration:
   per_second: 10000
   burst_count: 10000
+
+matrix_rtc:
+  transports:
+    - type: livekit
+      livekit_service_url: https://matrix-rtc.othersite.m.localhost/livekit/jwt

backend/playwright_homeserver.yaml

@@ -40,6 +40,15 @@ experimental_features:
   msc4222_enabled: true
   # sticky events for MatrixRTC user state
   msc4354_enabled: true
+  # MatrixRTC
+  msc4143_enabled: true
+  # Enable membership look-up via /is_joined.
+  msc4502_enabled: true
+  # Enable C-S & S-S request proxying for application services.
+  msc4512_enabled: true
+
+app_service_config_files:
+  - /data/cfg/app-service.yaml
 
 # The maximum allowed duration by which sent events can be delayed, as
 # per MSC4140. Must be a positive value if set.  Defaults to no
@@ -54,7 +63,6 @@ enable_registration_without_verification: true
 registration_shared_secret: "test_shared_secret_for_local_dev_only"
 
 report_stats: false
-serve_server_wellknown: true
 
 # Ratelimiting settings for client actions (registration, login, messaging).
 #
@@ -84,3 +92,8 @@ rc_login:
 rc_registration:
   per_second: 10000
   burst_count: 10000
+
+matrix_rtc:
+  transports:
+    - type: livekit
+      livekit_service_url: https://matrix-rtc.m.localhost/livekit/jwt

codecov.yml

@@ -0,0 +1,20 @@
+# Coverage comes from a single vitest run (see .github/workflows/test.yaml), so
+# the app and the SDK are split by path into codecov components rather than
+# uploaded under separate flags. Each component gets its own coverage figure in
+# the PR comment and on codecov.io.
+#
+# Validate with: curl --data-binary @codecov.yml https://codecov.io/validate
+
+comment:
+  layout: "reach, diff, flags, components, files"
+
+component_management:
+  individual_components:
+    - component_id: app
+      name: app
+      paths:
+        - src/**
+    - component_id: sdk
+      name: sdk
+      paths:
+        - sdk/**

component/CallPortalRoot.test.tsx

@@ -0,0 +1,57 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, test } from "vitest";
+import { render, screen } from "@testing-library/react";
+import { type ReactNode } from "react";
+import { Tooltip, TooltipProvider } from "@vector-im/compound-web";
+
+import { CallPortalRoot } from "./CallPortalRoot";
+
+// A button whose accessible name comes from its tooltip, as every icon button
+// in the call does: the name is lost whenever the tooltip has nowhere to go.
+const LabelledButton = (): ReactNode => (
+  <TooltipProvider>
+    <Tooltip label="Microphone">
+      <button>🎤</button>
+    </Tooltip>
+  </TooltipProvider>
+);
+
+test("floats into the host document with no root", () => {
+  render(
+    <CallPortalRoot root={undefined}>
+      <LabelledButton />
+    </CallPortalRoot>,
+  );
+  expect(screen.getByRole("button", { name: "Microphone" })).toBeTruthy();
+});
+
+test("floats into the root it is given", () => {
+  const root = document.createElement("div");
+  document.body.appendChild(root);
+  render(
+    <CallPortalRoot root={root}>
+      <LabelledButton />
+    </CallPortalRoot>,
+  );
+  const button = screen.getByRole("button", { name: "Microphone" });
+  const label = document.getElementById(
+    button.getAttribute("aria-labelledby")!,
+  );
+  expect(root.contains(label)).toBe(true);
+  root.remove();
+});
+
+test("waits for a root that is not available yet", () => {
+  render(
+    <CallPortalRoot root={null}>
+      <LabelledButton />
+    </CallPortalRoot>,
+  );
+  expect(screen.queryByRole("button", { name: "Microphone" })).toBeNull();
+});

component/CallPortalRoot.tsx

@@ -0,0 +1,26 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { type FC, type ReactNode } from "react";
+import { PortalRoot } from "@vector-im/compound-web";
+
+interface Props {
+  root: HTMLElement | null | undefined;
+  children: ReactNode;
+}
+
+/**
+ * Where Compound floats the call's menus and tooltips. With no `root` the call
+ * is not wrapped at all and they go into the host document's body; `null` is
+ * Compound's "not available yet", and the floating parts wait for it.
+ */
+export const CallPortalRoot: FC<Props> = ({ root, children }): ReactNode =>
+  root === undefined ? (
+    children
+  ) : (
+    <PortalRoot root={root}>{children}</PortalRoot>
+  );

component/ElementCall.module.css

@@ -0,0 +1,51 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+/* The container a host mounts us into. It fills whatever space the host gives
+it, and nothing we draw may leave it.
+
+That takes two separate things, which are easy to mistake for one. `isolation`
+gives us a stacking context, so nothing inside can be layered above the host's
+own interface. Containment makes us the containing block for `position: fixed`
+descendants, and clips what we paint to our own box: without it, the modal
+scrim and dialog — which are positioned `fixed` and centred, since in the app
+they are meant to cover the page — resolve against the viewport and appear in
+the middle of the host's window rather than in the middle of the call.
+
+The clipping cuts both ways: a menu near the edge of a small container is
+trimmed rather than overflowing into the host. That is the trade being a
+component rather than a page makes. */
+.root {
+  display: flex;
+  flex-direction: column;
+  inline-size: 100%;
+  block-size: 100%;
+  isolation: isolate;
+  contain: layout paint;
+  position: relative;
+  background-color: var(--cpd-color-bg-canvas-default);
+  color: var(--cpd-color-text-primary);
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  -webkit-tap-highlight-color: transparent;
+}
+
+/* The call itself. It is a stacking context of its own, as the standalone
+page's `#root` is, so that the layers the call view uses for its header, footer
+and overlays stay below the modals and toasts, which are portalled into the
+root and carry no layer of their own.
+
+What Compound floats — tooltips, menus — is not in here at all: it goes into
+the host's body, as it would for any other component on the host's page, and is
+styled and layered by the host's copy of Compound. */
+.content {
+  display: flex;
+  flex-direction: column;
+  block-size: 100%;
+  position: relative;
+  isolation: isolate;
+}

component/api.ts

@@ -0,0 +1,138 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+/**
+ * EXPERIMENTAL
+ *
+ * What a host needs in order to talk about Element Call, without Element Call:
+ * the component's props and the types they are made of, the handle and the
+ * host bridge, the intents a call can be started with and the configuration
+ * each implies.
+ *
+ * This is an entry point of its own, `@element-hq/element-call-component/api`,
+ * so that a host can import it on a path that must stay light — a call model
+ * that needs `BackgroundStyle.Solid` as a value, say — and load the component
+ * itself, and everything it brings, only when a call is shown. The main entry
+ * point re-exports all of it, so a host that does not care may import
+ * everything from there.
+ *
+ * Nothing in here may reach anything that is not a type or a constant: the
+ * point of this module is what it does not import.
+ */
+
+import type { Ref } from "react";
+import type { MatrixClient } from "matrix-js-sdk";
+
+import type { UrlProperties } from "../src/UrlParams";
+import type { ElementCallHandle, ElementCallHostBridge } from "./host";
+import {
+  BackgroundStyle,
+  configurationForIntent,
+  HeaderStyle,
+  type UrlConfiguration,
+  UserIntent,
+} from "../src/UrlConfiguration";
+
+// How the host and Element Call talk to each other, and what they say
+export type { ElementCallHandle, ElementCallHostBridge } from "./host";
+export type { DeviceMuteRequest, DeviceMuteState } from "../src/HostBridge";
+export type { JoinCallData } from "../src/widget";
+// The deployment-wide configuration, as distinct from ElementCallConfiguration
+// below, which is per call
+export type { ConfigOptions } from "../src/config/ConfigOptions";
+// The values that appear in ElementCallConfiguration and in the intent, and
+// what each intent means by default
+export {
+  BackgroundStyle,
+  configurationForIntent,
+  HeaderStyle,
+  type UrlConfiguration,
+  UserIntent,
+};
+
+/**
+ * How Element Call should behave. Everything is optional; anything left out
+ * takes the default that {@link ElementCallProps.intent} implies.
+ *
+ * This is the behaviour a widget can be configured with through its URL, plus
+ * the one fact about the call a host has a say in here, the background. The
+ * rest of what a widget's URL carries — who the user is, how to reach the
+ * homeserver, where to report analytics, the shared secret of a room that is
+ * encrypted with one — a component host supplies by other routes, or not at
+ * all; and what can change while the call is running, the theme and the
+ * language, is a prop of its own.
+ */
+export type ElementCallConfiguration = Partial<UrlConfiguration> &
+  Partial<Pick<UrlProperties, "background">>;
+
+export interface ElementCallProps {
+  /**
+   * The client to place the call with. Element Call does not authenticate
+   * anyone or manage a session of its own; this one is the host's.
+   */
+  client: MatrixClient;
+  /** The room to call in. The host's client must already know about it. */
+  roomId: string;
+  /**
+   * What the user asked for — whether they started the call or joined one that
+   * was already running, and whether it is a call in a group or a DM. Element
+   * Call decides what each of those means: whether to show the lobby first,
+   * whether to ring, and so on.
+   *
+   * Defaults to joining an existing group call, which is the most conservative
+   * reading, but a host that knows which button the user pressed should say so.
+   */
+  intent?: UserIntent;
+  /**
+   * How Element Call should behave, overriding whatever {@link intent} implies.
+   * A host that finds itself setting a lot of these probably wants a different
+   * intent instead.
+   *
+   * Compared by value, so it is fine to write this inline; only a change to
+   * what it says restarts anything.
+   */
+  config?: ElementCallConfiguration;
+  /**
+   * What Element Call tells the host while the call is running: that the user
+   * has joined or hung up, that it would like to be kept on screen, and so on.
+   * Without one, Element Call assumes nobody is listening.
+   */
+  hostBridge?: ElementCallHostBridge;
+  /**
+   * What the host tells Element Call: to hang up, to mute, to join. Available
+   * once the component has rendered.
+   */
+  ref?: Ref<ElementCallHandle>;
+  /**
+   * The theme to show Element Call in, `light` or `dark`. Left out, Element
+   * Call picks. Changes take effect at once, and cost nothing else.
+   */
+  theme?: string;
+  /**
+   * The language to show Element Call in, as a BCP 47 tag: one of the
+   * `supportedLanguages` the main entry point exports, or something that falls
+   * back to one (`de-AT` to `de`). Left out, the browser's language is used.
+   *
+   * Translations are one thing shared by every Element Call on the page, so
+   * the most recently set language wins for all of them.
+   */
+  language?: string;
+  /**
+   * Where the parts of Element Call that float above it — its menus and
+   * tooltips, which Compound portals out of the call — are rendered. Left out,
+   * they go into the host document's body, as they do for any other component
+   * on the host's page.
+   *
+   * A host that moves Element Call's DOM into another document, such as a
+   * Document Picture-in-Picture window, passes that document's body here so
+   * that a menu opens in the window its button is in. Changes take effect at
+   * once. `null` means the root is not available yet, as from a callback ref
+   * that has not fired: menus and tooltips wait for it rather than falling
+   * back to the body.
+   */
+  portalRoot?: HTMLElement | null;
+}

component/build/scopeStylesToRoot.test.ts

@@ -0,0 +1,112 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { describe, expect, it } from "vitest";
+import postcss from "postcss";
+
+import { ROOT_SELECTOR, scopeStylesToRoot } from "./scopeStylesToRoot";
+
+const inRoot = `:where(${ROOT_SELECTOR}, ${ROOT_SELECTOR} *)`;
+const isRoot = `:where(${ROOT_SELECTOR})`;
+
+async function scope(css: string, file = "base.css"): Promise<string> {
+  const result = await postcss([scopeStylesToRoot()]).process(css, {
+    from: file,
+  });
+  return result.css;
+}
+
+describe("scopeStylesToRoot", () => {
+  it("makes the root stand in for the document", async () => {
+    expect(await scope("html { line-height: 1.15 }")).toBe(
+      `${isRoot} { line-height: 1.15 }`,
+    );
+    expect(await scope("body { margin: 0 }")).toBe(`${isRoot} { margin: 0 }`);
+    expect(await scope(":root { --a: 1 }")).toBe(`${isRoot} { --a: 1 }`);
+    expect(await scope("body.no-scroll-body { position: fixed }")).toBe(
+      `${isRoot}.no-scroll-body { position: fixed }`,
+    );
+    expect(await scope("body .x { color: red }")).toBe(
+      `${isRoot} .x { color: red }`,
+    );
+  });
+
+  it("collapses selectors that all became the root", async () => {
+    expect(await scope("html, body, input { font: inherit }")).toBe(
+      `${isRoot},input${inRoot} { font: inherit }`,
+    );
+  });
+
+  it("confines everything else to the root and what is inside it", async () => {
+    expect(await scope("h1 { margin: 0 }")).toBe(`h1${inRoot} { margin: 0 }`);
+    expect(await scope(".cpd-theme-dark { --a: 1 }")).toBe(
+      `.cpd-theme-dark${inRoot} { --a: 1 }`,
+    );
+    expect(await scope("* { box-sizing: border-box }")).toBe(
+      `*${inRoot} { box-sizing: border-box }`,
+    );
+    expect(await scope(".a > .b + .c { color: red }")).toBe(
+      `.a>.b+.c${inRoot} { color: red }`,
+    );
+  });
+
+  it("keeps pseudo-elements last", async () => {
+    expect(await scope("button::-moz-focus-inner { border: 0 }")).toBe(
+      `button${inRoot}::-moz-focus-inner { border: 0 }`,
+    );
+    expect(await scope(".a .b:hover::after { content: '' }")).toBe(
+      `.a .b:hover${inRoot}::after { content: '' }`,
+    );
+    expect(await scope("p:first-letter { color: red }")).toBe(
+      `p${inRoot}:first-letter { color: red }`,
+    );
+  });
+
+  it("leaves alone what already names the root", async () => {
+    const css = `${ROOT_SELECTOR}[data-platform="ios"] { --a: 1 }`;
+    expect(await scope(css)).toBe(css);
+  });
+
+  it("reaches into layers and media queries", async () => {
+    expect(
+      await scope(
+        "@layer normalize { h1 { margin: 0 } } @media (min-width: 1px) { p { margin: 0 } }",
+      ),
+    ).toBe(
+      `@layer normalize { h1${inRoot} { margin: 0 } } @media (min-width: 1px) { p${inRoot} { margin: 0 } }`,
+    );
+  });
+
+  it("does not touch keyframes or nested rules", async () => {
+    expect(
+      await scope("@keyframes spin { from { opacity: 0 } to { opacity: 1 } }"),
+    ).toBe("@keyframes spin { from { opacity: 0 } to { opacity: 1 } }");
+    expect(
+      await scope(
+        ".a { color: red; &:hover { color: blue } .b { color: green } }",
+      ),
+    ).toBe(
+      `.a${inRoot} { color: red; &:hover { color: blue } .b { color: green } }`,
+    );
+  });
+
+  it("only touches the bare selectors of a CSS module", async () => {
+    const file = "Settings.module.css";
+    expect(await scope("pre { font-size: 1px }", file)).toBe(
+      `pre${inRoot} { font-size: 1px }`,
+    );
+    expect(await scope(".modal pre { font-size: 1px }", file)).toBe(
+      `.modal pre${inRoot} { font-size: 1px }`,
+    );
+    expect(await scope(".box_abc12 { border: 0 }", file)).toBe(
+      ".box_abc12 { border: 0 }",
+    );
+    expect(await scope(".a .b_abc12:hover { border: 0 }", file)).toBe(
+      ".a .b_abc12:hover { border: 0 }",
+    );
+  });
+});

component/build/scopeStylesToRoot.ts

@@ -0,0 +1,162 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import {
+  type AtRule,
+  type Container,
+  type Document,
+  type Plugin,
+  type Rule,
+} from "postcss";
+import selectorParser, {
+  type Node,
+  type Pseudo,
+  type Selector,
+} from "postcss-selector-parser";
+
+/**
+ * How the stylesheets find Element Call's root element. The attribute is put
+ * there by `useTheme`, on the container the host gives the component.
+ */
+export const ROOT_SELECTOR = "[data-element-call-root]";
+
+// Both are `:where()`, which has no specificity of its own, so the rules keep
+// exactly the weight they had before being scoped and nothing in Element Call's
+// cascade changes — only where it applies.
+//
+// The root, or anything inside it. Appended to the element a rule is about,
+// rather than prepended to the whole selector, so that a rule about the root
+// itself (its theme class, say) still matches.
+const IN_ROOT = `:where(${ROOT_SELECTOR}, ${ROOT_SELECTOR} *)`;
+// The root itself, standing in for the document.
+const IS_ROOT = `:where(${ROOT_SELECTOR})`;
+
+/**
+ * Confines a stylesheet to Element Call's root element, for the build of
+ * Element Call as a component.
+ *
+ * As a page of its own, Element Call can style the document: normalize.css and
+ * its own base styles speak of `html`, `body` and bare elements, and its custom
+ * properties are declared on `:root`. As a component, all of that would land on
+ * the host's document too. This rewrites every selector so that it matches only
+ * the root or its descendants:
+ *
+ * - `html`, `body` and `:root` become the root element, which is what stands in
+ *   for the document inside a host.
+ * - Everything else keeps its selector and gains `:where([data-element-call-root],
+ *   [data-element-call-root] *)` on the element it styles.
+ * - Selectors that already name the root are left alone, as are keyframe
+ *   selectors and rules nested inside another rule, which are relative to it.
+ *
+ * CSS modules are scoped by their class names already, so only their selectors
+ * that would match by element alone — `pre` rather than `.pre` — are touched.
+ *
+ * The root's custom properties are still inherited by everything inside it,
+ * the way they were from `:root`. Compound's own stylesheet — the design
+ * tokens, the component styles, the fonts — is not in this build at all: the
+ * host supplies it, unscoped, along with its copy of Compound.
+ */
+export function scopeStylesToRoot(): Plugin {
+  return {
+    postcssPlugin: "element-call-scope-styles-to-root",
+    Once(root) {
+      const isModule =
+        root.source?.input.file?.endsWith(".module.css") ?? false;
+      root.walkRules((rule) => {
+        if (isRelative(rule)) return;
+        rule.selector = (isModule ? scopeBare : scopeAll).processSync(
+          rule.selector,
+          { lossless: false },
+        );
+      });
+    },
+  };
+}
+
+/** Whether a rule's selectors are relative to something other than the document. */
+function isRelative(rule: Rule): boolean {
+  let parent: Container | Document | undefined = rule.parent;
+  while (parent !== undefined) {
+    if (parent.type === "rule") return true;
+    if (parent.type === "atrule") {
+      const { name } = parent as AtRule;
+      if (name.endsWith("keyframes") || name === "page") return true;
+    }
+    parent = parent.parent;
+  }
+  return false;
+}
+
+const processor = (isModule: boolean): ReturnType<typeof selectorParser> =>
+  selectorParser((selectors) => {
+    selectors.each((selector) => {
+      scopeSelector(selector, isModule);
+    });
+    // Mapping `html, body` onto the root leaves the same selector twice
+    const seen = new Set<string>();
+    selectors.each((selector) => {
+      const text = String(selector).trim();
+      if (seen.has(text)) selector.remove();
+      else seen.add(text);
+    });
+  });
+
+// Everything, for stylesheets that speak of the document; only what a class
+// does not already confine, for CSS modules
+const scopeAll = processor(false);
+const scopeBare = processor(true);
+
+function scopeSelector(selector: Selector, isModule: boolean): void {
+  if (String(selector).includes(ROOT_SELECTOR)) return;
+
+  const compounds = splitCompounds(selector);
+  if (compounds.length === 0) return;
+
+  // Something said of the document is said of the root instead
+  const document = compounds[0].find(isDocumentSelector);
+  if (document !== undefined) {
+    document.replaceWith(pseudo(IS_ROOT));
+    return;
+  }
+
+  const subject = compounds.at(-1)!;
+  if (isModule && subject.some((node) => node.type === "class")) return;
+
+  // Pseudo-elements have to come last in a compound selector
+  const pseudoElement = subject.find(isPseudoElement);
+  if (pseudoElement === undefined) selector.append(pseudo(IN_ROOT));
+  else selector.insertBefore(pseudoElement, pseudo(IN_ROOT));
+}
+
+/** The compound selectors making up a complex selector, in order. */
+function splitCompounds(selector: Selector): Node[][] {
+  const compounds: Node[][] = [[]];
+  for (const node of selector.nodes) {
+    if (node.type === "combinator") compounds.push([]);
+    else if (node.type !== "comment") compounds.at(-1)!.push(node);
+  }
+  return compounds.filter((compound) => compound.length > 0);
+}
+
+function isDocumentSelector(node: Node): boolean {
+  return (
+    (node.type === "tag" && (node.value === "html" || node.value === "body")) ||
+    (node.type === "pseudo" && node.value === ":root")
+  );
+}
+
+function isPseudoElement(node: Node): node is Pseudo {
+  if (node.type !== "pseudo") return false;
+  return (
+    node.value.startsWith("::") ||
+    [":before", ":after", ":first-line", ":first-letter"].includes(node.value)
+  );
+}
+
+function pseudo(text: string): Pseudo {
+  return selectorParser().astSync(text).nodes[0].nodes[0].clone() as Pseudo;
+}

component/dev/DevHostBridge.ts

@@ -0,0 +1,46 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { type ElementCallHostBridge } from "../index";
+
+/**
+ * A host bridge that reports everything it is told, so that the harness can
+ * watch what Element Call says to its host. (What the host says to Element
+ * Call goes through the component's handle, and is logged by the pane.)
+ */
+export function createDevHostBridge(
+  log: (message: string) => void,
+  /** What the host does when Element Call asks to be closed. */
+  onClose: () => void,
+): ElementCallHostBridge {
+  /**
+   * Records something Element Call told the host. Nothing is sent anywhere, so
+   * this is only asynchronous because a real host's answer would have to be.
+   */
+  const told = async (message: string): Promise<void> => {
+    log(`→ ${message}`);
+    await Promise.resolve();
+  };
+
+  return {
+    setAlwaysOnScreen: async (alwaysOnScreen): Promise<void> =>
+      await told(`setAlwaysOnScreen(${alwaysOnScreen})`),
+    contentLoaded: async (): Promise<void> => await told("contentLoaded"),
+    notifyJoined: async (): Promise<void> => await told("notifyJoined"),
+    notifyHungUp: async (): Promise<void> => await told("notifyHungUp"),
+    notifyDeviceMute: async (state): Promise<void> =>
+      await told(
+        `notifyDeviceMute(audio: ${state.audio_enabled}, video: ${state.video_enabled})`,
+      ),
+    // Present because this host really can dismiss Element Call, which is what
+    // makes it offer a close affordance at all
+    close: async (): Promise<void> => {
+      await told("close");
+      onClose();
+    },
+  };
+}

component/dev/Harness.module.css

@@ -0,0 +1,140 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+.credentials {
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+  max-inline-size: 420px;
+  margin: 48px auto;
+  padding: 24px;
+  background-color: #ffffff;
+  border: 1px solid #d4d4d8;
+  border-radius: 8px;
+}
+
+.field {
+  display: flex;
+  flex-direction: column;
+  gap: 4px;
+}
+
+.error {
+  color: #b91c1c;
+}
+
+.harness {
+  display: grid;
+  grid-template-rows: auto 1fr auto;
+  block-size: 100%;
+}
+
+.header,
+.paneBar {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  padding: 8px 12px;
+  border-block-end: 1px solid #d4d4d8;
+  background-color: #ffffff;
+}
+
+.header h1 {
+  font-size: 16px;
+  margin: 0;
+}
+
+.middle {
+  display: flex;
+  min-block-size: 0;
+}
+
+.sidebar {
+  flex: 0 0 220px;
+  padding: 12px;
+  border-inline-end: 1px solid #d4d4d8;
+  background-color: #ffffff;
+  overflow-y: auto;
+}
+
+.panes {
+  display: flex;
+  flex-wrap: wrap;
+  /* So that a pane is the size it was dragged to, rather than being stretched
+  to fill the row */
+  align-items: flex-start;
+  align-content: flex-start;
+  gap: 16px;
+  padding: 16px;
+  flex: 1;
+  min-inline-size: 0;
+  overflow: auto;
+}
+
+.pane {
+  display: flex;
+  flex-direction: column;
+  border: 1px solid #d4d4d8;
+  border-radius: 8px;
+  overflow: hidden;
+  background-color: #ffffff;
+}
+
+.paneBar {
+  flex-wrap: wrap;
+  gap: 6px;
+  border-block-end: none;
+}
+
+/* The space the host gives Element Call. Resizable so that the sizes it has to
+cope with can be found by dragging rather than by rebuilding, and `overflow:
+hidden` both to enable the resize handle and to show up anything inside Element
+Call that does not fit the box it was given. */
+.paneCall {
+  inline-size: 560px;
+  block-size: 420px;
+  min-inline-size: 180px;
+  min-block-size: 180px;
+  resize: both;
+  overflow: hidden;
+}
+
+.log {
+  max-block-size: 180px;
+  overflow-y: auto;
+  padding: 8px 12px;
+  border-block-start: 1px solid #d4d4d8;
+  background-color: #ffffff;
+  font-size: 12px;
+}
+
+.log h2 {
+  font-size: 13px;
+  margin: 0 0 4px;
+}
+
+.log ol {
+  margin: 0;
+  padding: 0;
+  list-style: none;
+}
+
+/* A host overlay, which Element Call must not be able to draw over */
+.dialogScrim {
+  position: fixed;
+  inset: 0;
+  display: grid;
+  place-items: center;
+  background-color: rgb(0 0 0 / 50%);
+  z-index: 10;
+}
+
+.dialog {
+  padding: 24px;
+  border-radius: 8px;
+  background-color: #ffffff;
+}

component/dev/Harness.tsx

@@ -0,0 +1,380 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import {
+  type FC,
+  type FormEvent,
+  type ReactNode,
+  useCallback,
+  useMemo,
+  useRef,
+  useState,
+} from "react";
+import { type MatrixClient } from "matrix-js-sdk";
+import { logger } from "matrix-js-sdk/lib/logger";
+
+import {
+  ElementCall,
+  type ElementCallHandle,
+  supportedLanguages,
+} from "../index";
+import { createDevHostBridge } from "./DevHostBridge";
+import { createSession, joinRoom } from "./session";
+import styles from "./Harness.module.css";
+
+interface Credentials {
+  homeserver: string;
+  username: string;
+  password: string;
+  room: string;
+}
+
+const CREDENTIALS_KEY = "element-call-component-harness";
+
+const DEFAULT_CREDENTIALS: Credentials = {
+  homeserver: "https://synapse.m.localhost",
+  username: "",
+  password: "",
+  room: "",
+};
+
+/**
+ * The credentials to start with: the last ones used, so that a reload does not
+ * mean typing them again, overridden by anything in the query string.
+ *
+ * A host reading its own URL is entirely proper — it was Element Call doing so
+ * that was the mistake. It lets the end-to-end tests, or a shared link, say
+ * which account and room to use.
+ */
+function loadCredentials(): Credentials {
+  let stored: Partial<Credentials> = {};
+  try {
+    const json = localStorage.getItem(CREDENTIALS_KEY);
+    if (json !== null) stored = JSON.parse(json) as Credentials;
+  } catch (e) {
+    logger.warn("Could not read the stored harness credentials", e);
+  }
+
+  const query = new URLSearchParams(location.search);
+  const fromUrl = Object.fromEntries(
+    (["homeserver", "username", "password", "room"] as const)
+      .map((name) => [name, query.get(name)])
+      .filter(([, value]) => value !== null),
+  ) as Partial<Credentials>;
+
+  return { ...DEFAULT_CREDENTIALS, ...stored, ...fromUrl };
+}
+
+interface Session {
+  label: string;
+  client: MatrixClient;
+}
+
+type State =
+  | { phase: "credentials" }
+  | { phase: "starting"; progress: string }
+  | { phase: "started"; roomId: string; sessions: Session[] }
+  | { phase: "failed"; error: string };
+
+interface LogEntry {
+  pane: string;
+  message: string;
+  at: string;
+}
+
+/**
+ * One Element Call component, with the controls a host would have over it: the
+ * requests it can make of Element Call, and the ability to take it off screen
+ * altogether.
+ */
+const Pane: FC<{
+  session: Session;
+  roomId: string;
+  theme: string | undefined;
+  language: string | undefined;
+  log: (pane: string, message: string) => void;
+}> = ({ session, roomId, theme, language, log }): ReactNode => {
+  const [mounted, setMounted] = useState(true);
+
+  const bridge = useMemo(
+    () =>
+      createDevHostBridge(
+        (message) => log(session.label, message),
+        () => setMounted(false),
+      ),
+    [log, session.label],
+  );
+
+  // What the host asks of Element Call goes through the component's handle.
+  // Worth saying out loud when a request is refused — asking to hang up when
+  // there is no call, say — since that is the sort of thing the harness is for.
+  const handle = useRef<ElementCallHandle>(null);
+  const ask = (
+    name: string,
+    make: (handle: ElementCallHandle) => Promise<unknown>,
+  ): void => {
+    if (handle.current === null) {
+      log(session.label, `← ${name}: not mounted`);
+      return;
+    }
+    log(session.label, `← ${name}`);
+    make(handle.current).then(
+      (reply) =>
+        log(
+          session.label,
+          `→ ${name} acknowledged${reply === undefined ? "" : `: ${JSON.stringify(reply)}`}`,
+        ),
+      (e: unknown) => log(session.label, `→ ${name} refused: ${e}`),
+    );
+  };
+
+  return (
+    <section className={styles.pane} data-testid="call-pane">
+      <div className={styles.paneBar}>
+        <strong>{session.label}</strong>
+        <code>{session.client.getDeviceId()}</code>
+        <button onClick={(): void => setMounted((m) => !m)}>
+          {mounted ? "Unmount" : "Mount"}
+        </button>
+        <button
+          onClick={(): void =>
+            ask(
+              "setDeviceMute(audio: false)",
+              async (h) => await h.setDeviceMute({ audio_enabled: false }),
+            )
+          }
+        >
+          Mute
+        </button>
+        <button
+          onClick={(): void => ask("hangUp", async (h) => await h.hangUp())}
+        >
+          Hang up
+        </button>
+      </div>
+      {/* Resizable, because how Element Call copes with the size it is given is
+      one of the things we cannot find out from the standalone app */}
+      <div className={styles.paneCall} data-testid="call-container">
+        {mounted && (
+          <ElementCall
+            ref={handle}
+            client={session.client}
+            roomId={roomId}
+            hostBridge={bridge}
+            theme={theme}
+            language={language}
+          />
+        )}
+      </div>
+    </section>
+  );
+};
+
+/** Host furniture, to make it visible if Element Call styles anything but itself. */
+const HostChrome: FC = (): ReactNode => (
+  <nav className={styles.sidebar}>
+    <h2>Host chrome</h2>
+    <p>
+      This column belongs to the host. If Element Call&apos;s stylesheet reaches
+      outside its own container, it shows up here.
+    </p>
+    <hr />
+    <ul>
+      <li>Some room</li>
+      <li>Another room</li>
+    </ul>
+    <button>A host button</button>
+  </nav>
+);
+
+/**
+ * A dialog of the host's own, over the top of the calls. Element Call as a
+ * component has to sit underneath this — being unable to is one of the reasons
+ * for a component rather than an iframe.
+ */
+const HostDialog: FC<{ onClose: () => void }> = ({ onClose }): ReactNode => (
+  <div className={styles.dialogScrim}>
+    <div className={styles.dialog}>
+      <h2>A dialog belonging to the host</h2>
+      <p>This should cover the calls completely.</p>
+      <button onClick={onClose}>Close</button>
+    </div>
+  </div>
+);
+
+/**
+ * Stands in for a host application using the Element Call component: it owns the Matrix
+ * clients, the page and the space each call is given, and reaches Element Call
+ * only through the component's public interface.
+ *
+ * Two calls at once, from two devices of the same account, so that a real call
+ * happens between them and anything Element Call keeps once per process rather
+ * than once per call shows itself.
+ */
+export const Harness: FC = (): ReactNode => {
+  const [credentials, setCredentials] = useState(loadCredentials);
+  const [state, setState] = useState<State>({ phase: "credentials" });
+  const [entries, setEntries] = useState<LogEntry[]>([]);
+  const [dialogOpen, setDialogOpen] = useState(false);
+  // The host's language setting, which Element Call follows. Undefined means
+  // the host has none and Element Call uses the browser's.
+  const [language, setLanguage] = useState<string | undefined>(undefined);
+  const [theme, setTheme] = useState<string | undefined>(undefined);
+
+  const log = useCallback((pane: string, message: string): void => {
+    setEntries((entries) =>
+      [
+        ...entries,
+        { pane, message, at: new Date().toLocaleTimeString() },
+      ].slice(-100),
+    );
+  }, []);
+
+  const start = useCallback(
+    (event: FormEvent): void => {
+      event.preventDefault();
+      localStorage.setItem(CREDENTIALS_KEY, JSON.stringify(credentials));
+      const { homeserver, username, password, room } = credentials;
+
+      const progress = (message: string): void =>
+        setState({ phase: "starting", progress: message });
+      progress("Starting");
+
+      void (async (): Promise<void> => {
+        try {
+          // One at a time: two logins at once from the same account is the
+          // shape of request homeservers rate limit
+          const sessions: Session[] = [];
+          for (const label of ["Call A", "Call B"])
+            sessions.push({
+              label,
+              client: await createSession(
+                homeserver,
+                username,
+                password,
+                (message) => progress(`${label}: ${message}`),
+              ),
+            });
+
+          progress("Joining the room");
+          let roomId = room;
+          for (const { client } of sessions)
+            roomId = await joinRoom(client, roomId);
+
+          setState({ phase: "started", roomId, sessions });
+        } catch (e) {
+          logger.error("The harness could not start", e);
+          setState({ phase: "failed", error: `${e}` });
+        }
+      })();
+    },
+    [credentials],
+  );
+
+  const field = (
+    name: keyof Credentials,
+    label: string,
+    type = "text",
+  ): ReactNode => (
+    <label className={styles.field}>
+      {label}
+      <input
+        type={type}
+        value={credentials[name]}
+        onChange={(e): void =>
+          setCredentials((c) => ({ ...c, [name]: e.target.value }))
+        }
+      />
+    </label>
+  );
+
+  if (state.phase !== "started")
+    return (
+      <form className={styles.credentials} onSubmit={start}>
+        <h1>Element Call component harness</h1>
+        <p>
+          Signs in twice and shows the Element Call component twice, in a page
+          that is not Element Call&apos;s own.
+        </p>
+        {field("homeserver", "Homeserver")}
+        {field("username", "Username")}
+        {field("password", "Password", "password")}
+        {field("room", "Room ID or alias")}
+        <button type="submit" disabled={state.phase === "starting"}>
+          Start
+        </button>
+        {state.phase === "starting" && <p>{state.progress}</p>}
+        {state.phase === "failed" && (
+          <p className={styles.error}>{state.error}</p>
+        )}
+      </form>
+    );
+
+  return (
+    <div className={styles.harness}>
+      <header className={styles.header}>
+        <h1>Element Call component harness</h1>
+        <code>{state.roomId}</code>
+        <button onClick={(): void => setDialogOpen(true)}>
+          Open a host dialog
+        </button>
+        <label>
+          Theme{" "}
+          <select
+            value={theme ?? ""}
+            onChange={(e): void => setTheme(e.target.value || undefined)}
+          >
+            <option value="">Element Call&apos;s choice</option>
+            <option value="light">light</option>
+            <option value="dark">dark</option>
+          </select>
+        </label>
+        <label>
+          Language{" "}
+          <select
+            value={language ?? ""}
+            onChange={(e): void => setLanguage(e.target.value || undefined)}
+          >
+            <option value="">Browser default</option>
+            {supportedLanguages.map((tag) => (
+              <option key={tag} value={tag}>
+                {tag}
+              </option>
+            ))}
+          </select>
+        </label>
+      </header>
+      <div className={styles.middle}>
+        <HostChrome />
+        <main className={styles.panes}>
+          {state.sessions.map((session) => (
+            <Pane
+              key={session.label}
+              session={session}
+              roomId={state.roomId}
+              theme={theme}
+              language={language}
+              log={log}
+            />
+          ))}
+        </main>
+      </div>
+      <section className={styles.log} data-testid="bridge-log">
+        <h2>Host bridge</h2>
+        <ol>
+          {entries.map((entry, i) => (
+            <li key={i}>
+              <code>{entry.at}</code> <strong>{entry.pane}</strong>{" "}
+              {entry.message}
+            </li>
+          ))}
+        </ol>
+      </section>
+      {dialogOpen && <HostDialog onClose={(): void => setDialogOpen(false)} />}
+    </div>
+  );
+};

component/dev/host.css

@@ -0,0 +1,23 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+/* The host page's own styles. Deliberately plain, and deliberately not using
+Element Call's design tokens: the harness should look like it does because of
+this file, not because Element Call styled it. */
+
+html,
+body,
+#root {
+  height: 100%;
+}
+
+body {
+  margin: 0;
+  font-family: system-ui, sans-serif;
+  background-color: #f4f4f5;
+  color: #18181b;
+}

component/dev/index.html

@@ -0,0 +1,21 @@
+<!doctype html>
+<!--
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+-->
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Element Call component harness</title>
+  </head>
+  <body>
+    <!-- Deliberately plain: this page stands in for a host application, so
+    anything it looks like must have come from the host's own styles or from
+    Element Call reaching outside its container. -->
+    <div id="root"></div>
+    <script type="module" src="./main.tsx"></script>
+  </body>
+</html>

component/dev/main.tsx

@@ -0,0 +1,52 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { StrictMode } from "react";
+import { createRoot } from "react-dom/client";
+import { logger } from "matrix-js-sdk/lib/logger";
+
+// What a host provides along with its copy of Compound: its stylesheet, the
+// design tokens and the fonts they name. The component does not bundle them.
+import "@fontsource/inter/400.css";
+import "@fontsource/inter/500.css";
+import "@fontsource/inter/600.css";
+import "@fontsource/inter/700.css";
+import "@fontsource/inconsolata/400.css";
+import "@fontsource/inconsolata/700.css";
+import "@vector-im/compound-design-tokens/assets/web/css/compound-design-tokens.css";
+import "@vector-im/compound-web/dist/style.css";
+import { type ConfigOptions, initializeElementCall } from "../index";
+import { Harness } from "./Harness";
+// After Element Call's, so that the host has the last word on its own page
+import "./host.css";
+
+/**
+ * The development app's own `config.json`, so that the harness runs Element
+ * Call the way `pnpm dev` does. It is not in the repository — developers copy
+ * it from `config/config.devenv.json` — so its absence is expected rather than
+ * an error.
+ */
+async function loadConfig(): Promise<ConfigOptions> {
+  try {
+    const response = await fetch("/config.json");
+    if (response.ok) return (await response.json()) as ConfigOptions;
+    logger.warn(
+      `No config.json (${response.status}); running with Element Call's defaults`,
+    );
+  } catch (e) {
+    logger.warn("Could not read config.json", e);
+  }
+  return {};
+}
+
+await initializeElementCall(await loadConfig());
+
+createRoot(document.getElementById("root")!).render(
+  <StrictMode>
+    <Harness />
+  </StrictMode>,
+);

component/dev/session.ts

@@ -0,0 +1,79 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import {
+  ClientEvent,
+  createClient,
+  type MatrixClient,
+  MemoryStore,
+  SyncState,
+} from "matrix-js-sdk";
+
+/**
+ * Logs in and brings up a client the way a host application would, so that the
+ * component is handed a real one rather than something Element Call built for
+ * itself.
+ *
+ * Everything is kept in memory and a fresh login happens on every reload. That
+ * costs a device on the development homeserver each time, which is harmless,
+ * and buys the harness two clients that cannot tread on each other's storage.
+ * Persisting the login to make reloads quicker would mean persisting the
+ * crypto store too: reusing a device ID with a fresh crypto store generates new
+ * device keys, and uploading them conflicts with the ones the server already
+ * holds.
+ */
+export async function createSession(
+  homeserver: string,
+  username: string,
+  password: string,
+  onProgress: (message: string) => void,
+): Promise<MatrixClient> {
+  onProgress("Logging in");
+  const login = await createClient({ baseUrl: homeserver }).login(
+    "m.login.password",
+    { identifier: { type: "m.id.user", user: username }, password },
+  );
+
+  const client = createClient({
+    baseUrl: homeserver,
+    accessToken: login.access_token,
+    userId: login.user_id,
+    deviceId: login.device_id,
+    store: new MemoryStore(),
+    useAuthorizationHeader: true,
+    fallbackICEServerAllowed: true,
+  });
+
+  onProgress(`Setting up crypto for ${login.device_id}`);
+  await client.initRustCrypto({ useIndexedDB: false });
+
+  onProgress(`Syncing ${login.device_id}`);
+  await client.startClient();
+  await new Promise<void>((resolve) => {
+    const onSync = (state: SyncState): void => {
+      if (state !== SyncState.Prepared && state !== SyncState.Syncing) return;
+      client.off(ClientEvent.Sync, onSync);
+      resolve();
+    };
+    client.on(ClientEvent.Sync, onSync);
+  });
+
+  return client;
+}
+
+/**
+ * The room to call in, joining it if this session is not in it yet — a host
+ * hands Element Call a room it already knows about, so the harness has to get
+ * itself into that position first.
+ */
+export async function joinRoom(
+  client: MatrixClient,
+  roomIdOrAlias: string,
+): Promise<string> {
+  const room = await client.joinRoom(roomIdOrAlias);
+  return room.roomId;
+}

component/host.test.ts

@@ -0,0 +1,161 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { renderHook } from "@testing-library/react";
+import { createRef } from "react";
+import { describe, expect, test, vi } from "vitest";
+
+import {
+  type ElementCallHandle,
+  type ElementCallHostBridge,
+  useComponentHostBridge,
+} from "./host";
+
+describe("useComponentHostBridge", () => {
+  test("keeps one identity while the host supplies new objects", () => {
+    const { result, rerender } = renderHook(
+      ({ supplied }: { supplied: ElementCallHostBridge }) =>
+        useComponentHostBridge(supplied, undefined, undefined),
+      { initialProps: { supplied: {} } },
+    );
+    const first = result.current;
+    rerender({ supplied: { notifyJoined: async () => {} } });
+    expect(result.current).toBe(first);
+  });
+
+  test("forwards to whatever the host most recently supplied", async () => {
+    const before = vi.fn().mockResolvedValue(undefined);
+    const after = vi.fn().mockResolvedValue(undefined);
+    const { result, rerender } = renderHook(
+      ({ supplied }: { supplied: ElementCallHostBridge }) =>
+        useComponentHostBridge(supplied, undefined, undefined),
+      { initialProps: { supplied: { notifyJoined: before } } },
+    );
+    rerender({ supplied: { notifyJoined: after } });
+
+    await result.current.notifyJoined();
+    expect(before).not.toHaveBeenCalled();
+    expect(after).toHaveBeenCalledOnce();
+  });
+
+  test("is quiet about what the host did not implement", async () => {
+    const { result } = renderHook(() =>
+      useComponentHostBridge(undefined, undefined, undefined),
+    );
+    await expect(result.current.contentLoaded()).resolves.toBeUndefined();
+    await expect(
+      result.current.notifyDeviceMute({
+        audio_enabled: true,
+        video_enabled: false,
+      }),
+    ).resolves.toBeUndefined();
+    expect(result.current.supportsReactions).toBe(true);
+    // Starting the user unmuted unasked is something a host has to opt into
+    expect(result.current.allowJoinUnmutedViaIntent).toBe(false);
+  });
+
+  test("lets the host allow joining unmuted on the intent", () => {
+    const { result, rerender } = renderHook(
+      ({ supplied }: { supplied: ElementCallHostBridge }) =>
+        useComponentHostBridge(supplied, undefined, undefined),
+      { initialProps: { supplied: {} } },
+    );
+    expect(result.current.allowJoinUnmutedViaIntent).toBe(false);
+
+    // Read through to whatever the host most recently said
+    rerender({ supplied: { allowJoinUnmutedViaIntent: true } });
+    expect(result.current.allowJoinUnmutedViaIntent).toBe(true);
+  });
+
+  test("only has a close when the host has one, since that is a signal", () => {
+    const { result, rerender } = renderHook(
+      ({ supplied }: { supplied: ElementCallHostBridge }) =>
+        useComponentHostBridge(supplied, undefined, undefined),
+      { initialProps: { supplied: {} } },
+    );
+    expect(result.current.close).toBeUndefined();
+
+    const close = vi.fn().mockResolvedValue(undefined);
+    rerender({ supplied: { close } });
+    expect(result.current.close).toBeDefined();
+  });
+
+  test("never offers profile changes, since the account is the host's", () => {
+    const { result } = renderHook(() =>
+      useComponentHostBridge(undefined, undefined, undefined),
+    );
+    expect(result.current.supportsProfileChanges).toBe(false);
+  });
+
+  describe("the handle", () => {
+    test("delivers a request to what is listening and resolves on its reply", async () => {
+      const ref = createRef<ElementCallHandle>();
+      const { result } = renderHook(() =>
+        useComponentHostBridge(undefined, ref, undefined),
+      );
+
+      const received = vi.fn();
+      result.current.deviceMute$.subscribe(({ data, reply }) => {
+        received(data);
+        reply({ audio_enabled: data.audio_enabled!, video_enabled: true });
+      });
+
+      await expect(
+        ref.current!.setDeviceMute({ audio_enabled: false }),
+      ).resolves.toEqual({ audio_enabled: false, video_enabled: true });
+      expect(received).toHaveBeenCalledWith({ audio_enabled: false });
+    });
+
+    test("refuses a request nothing in Element Call is listening for", async () => {
+      const ref = createRef<ElementCallHandle>();
+      renderHook(() => useComponentHostBridge(undefined, ref, undefined));
+
+      await expect(ref.current!.hangUp()).rejects.toThrow(
+        "Nothing in Element Call can hang up right now",
+      );
+    });
+  });
+
+  describe("the theme", () => {
+    test("reaches a subscriber that arrives after it was set", () => {
+      const { result } = renderHook(() =>
+        useComponentHostBridge(undefined, undefined, "light"),
+      );
+      const names: (string | undefined)[] = [];
+      result.current.themeChange$.subscribe(({ data }) =>
+        names.push(data.name),
+      );
+      expect(names).toEqual(["light"]);
+    });
+
+    test("follows the prop", () => {
+      const { result, rerender } = renderHook(
+        ({ theme }: { theme: string | undefined }) =>
+          useComponentHostBridge(undefined, undefined, theme),
+        { initialProps: { theme: "light" } },
+      );
+      const names: (string | undefined)[] = [];
+      result.current.themeChange$.subscribe(({ data }) =>
+        names.push(data.name),
+      );
+
+      rerender({ theme: "dark" });
+      expect(names).toEqual(["light", "dark"]);
+    });
+
+    test("says nothing when the host leaves the theme to Element Call", () => {
+      const { result } = renderHook(() =>
+        useComponentHostBridge(undefined, undefined, undefined),
+      );
+      const names: (string | undefined)[] = [];
+      result.current.themeChange$.subscribe(({ data }) =>
+        names.push(data.name),
+      );
+      expect(names).toEqual([]);
+    });
+  });
+});

component/host.ts

@@ -0,0 +1,201 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+/**
+ * How a host application and the Element Call component talk to each other.
+ *
+ * Inside Element Call the host is a {@link HostBridge}, which carries the
+ * host's requests as rxjs observables because that is what the widget API and
+ * the view models work in. A host should not have to know about rxjs, or agree
+ * with us on a version of it, so a component host sees neither: it implements
+ * plain async callbacks for what Element Call tells it, and makes its own
+ * requests through an imperative handle on the component, the way it would
+ * call `play()` on a video element. This module adapts the one to the other.
+ */
+
+import { type Ref, useEffect, useImperativeHandle } from "react";
+import { ReplaySubject, Subject } from "rxjs";
+
+import {
+  type DeviceMuteRequest,
+  type DeviceMuteState,
+  type HostBridge,
+  type HostRequest,
+} from "../src/HostBridge";
+import { type JoinCallData } from "../src/widget";
+import { useInitial } from "../src/useInitial";
+import { useLatest } from "../src/useLatest";
+
+/**
+ * What Element Call tells the application hosting it as a component.
+ * Everything is optional: a host implements what it wants to hear about.
+ *
+ * Compared by nothing — Element Call always calls whichever one it was most
+ * recently given, so this may be written inline.
+ */
+export interface ElementCallHostBridge {
+  /**
+   * Asks the host to keep Element Call on screen (or stop doing so), so that a
+   * call in progress is not torn down when the user navigates elsewhere.
+   */
+  setAlwaysOnScreen?(alwaysOnScreen: boolean): Promise<void>;
+  /** Tells the host that Element Call has finished loading. */
+  contentLoaded?(): Promise<void>;
+  /** Tells the host that the user has joined the call. */
+  notifyJoined?(): Promise<void>;
+  /** Tells the host that the user has hung up. */
+  notifyHungUp?(): Promise<void>;
+  /** Tells the host the user's current audio and video mute state. */
+  notifyDeviceMute?(state: DeviceMuteState): Promise<void>;
+  /**
+   * Asks the host to close Element Call: to unmount the component. Its
+   * presence is what makes Element Call offer a close button on its error
+   * screens, and leave the host to decide what is shown once a call has ended.
+   * Without it, Element Call shows its own post-call screen, if it has one for
+   * the situation, or nothing.
+   */
+  close?(): Promise<void>;
+  /**
+   * Whether Element Call may send and receive reactions in this room.
+   * Defaults to true.
+   */
+  readonly supportsReactions?: boolean;
+  /**
+   * Whether the user may start unmuted when the intent skips the lobby, so
+   * that they never see their devices before joining. Defaults to false: the
+   * user starts muted and unmutes themselves. A host that chose the intent on
+   * the user's behalf, and is sure they expect to be heard and seen at once,
+   * says so here — as a Matrix client hosting Element Call as a widget does.
+   */
+  readonly allowJoinUnmutedViaIntent?: boolean;
+}
+
+/**
+ * What a host can ask of a mounted Element Call, reached through the
+ * component's `ref`. Each request resolves once Element Call has acted on it,
+ * and rejects if nothing in Element Call is in a position to act: hanging up
+ * when there is no call, say.
+ */
+export interface ElementCallHandle {
+  /**
+   * Joins the call, when Element Call was configured to `preload` and is
+   * waiting to be told to. Says which devices to join with.
+   */
+  join(devices: JoinCallData): Promise<void>;
+  /** Leaves the call. */
+  hangUp(): Promise<void>;
+  /**
+   * Changes the mute state, for whichever of audio and video is given, and
+   * reports the state that results.
+   */
+  setDeviceMute(request: DeviceMuteRequest): Promise<DeviceMuteState>;
+}
+
+/** Hands a request to Element Call and waits for it to be acknowledged. */
+async function request<Data, Reply>(
+  listeners: Subject<HostRequest<Data, Reply>>,
+  what: string,
+  data: Data,
+): Promise<Reply> {
+  if (!listeners.observed)
+    throw new Error(`Nothing in Element Call can ${what} right now`);
+  return await new Promise((resolve) =>
+    listeners.next({ data, reply: resolve }),
+  );
+}
+
+/**
+ * The {@link HostBridge} the rest of Element Call sees, built from what a
+ * component host supplies and wired to the handle it is given.
+ *
+ * The bridge is created once and never changes identity — everything that
+ * depends on it would otherwise restart when the host re-rendered with a new
+ * object — and forwards each call to whatever the host most recently passed.
+ */
+export function useComponentHostBridge(
+  supplied: ElementCallHostBridge | undefined,
+  ref: Ref<ElementCallHandle> | undefined,
+  /** The theme the host wants, or undefined to leave it to Element Call. */
+  theme: string | undefined,
+): HostBridge {
+  const latest = useLatest(supplied ?? {});
+
+  const requests = useInitial(() => ({
+    // The theme is state, not an event: a `theme` prop rather than a request
+    // on the handle. It travels this channel because that is how the rest of
+    // Element Call hears about a host's theme, and replays so that whatever
+    // subscribes after the host has set it — everything, on first render —
+    // still hears the current one.
+    themeChange$: new ReplaySubject<HostRequest<{ name?: string }>>(1),
+    join$: new Subject<HostRequest<JoinCallData>>(),
+    hangUp$: new Subject<HostRequest<Record<string, never>>>(),
+    deviceMute$: new Subject<HostRequest<DeviceMuteRequest, DeviceMuteState>>(),
+  }));
+
+  useEffect(() => {
+    if (theme !== undefined)
+      requests.themeChange$.next({ data: { name: theme }, reply: () => {} });
+  }, [requests, theme]);
+
+  const bridge = useInitial((): HostBridge => ({
+    setAlwaysOnScreen: async (alwaysOnScreen) => {
+      await latest.current.setAlwaysOnScreen?.(alwaysOnScreen);
+    },
+    contentLoaded: async () => {
+      await latest.current.contentLoaded?.();
+    },
+    notifyJoined: async () => {
+      await latest.current.notifyJoined?.();
+    },
+    notifyHungUp: async () => {
+      await latest.current.notifyHungUp?.();
+    },
+    notifyDeviceMute: async (state) => {
+      await latest.current.notifyDeviceMute?.(state);
+    },
+    // Whether these exist is itself information, so they are read through
+    // rather than wrapped unconditionally
+    get close() {
+      const close = latest.current.close;
+      return close === undefined
+        ? undefined
+        : async (): Promise<void> => await close();
+    },
+    // Not offered to a component host: the client it hands over holds the
+    // credentials to fetch media itself. A widget's client does not, which
+    // is what the internal bridge's `downloadMedia` is for.
+    get supportsReactions(): boolean {
+      return latest.current.supportsReactions ?? true;
+    },
+    get allowJoinUnmutedViaIntent(): boolean {
+      return latest.current.allowJoinUnmutedViaIntent ?? false;
+    },
+    // Whatever the host says or does not say, the account is its own: it
+    // signed the user in and handed us the client. So Element Call never
+    // offers to edit the profile from inside a component.
+    supportsProfileChanges: false,
+    ...requests,
+  }));
+
+  useImperativeHandle(
+    ref,
+    (): ElementCallHandle => ({
+      join: async (devices) =>
+        await request(requests.join$, "join a call", devices),
+      hangUp: async () => await request(requests.hangUp$, "hang up", {}),
+      setDeviceMute: async (muteRequest) =>
+        await request(
+          requests.deviceMute$,
+          "change the mute state",
+          muteRequest,
+        ),
+    }),
+    [requests],
+  );
+
+  return bridge;
+}

component/index.tsx

@@ -0,0 +1,282 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+/**
+ * EXPERIMENTAL
+ *
+ * Element Call as a React component, for an application that wants to show a
+ * call inside itself rather than in an iframe.
+ *
+ * The host supplies the client and says which room to call in; Element Call
+ * supplies the call. Everything it would otherwise take from the page it is on
+ * — the URL, the document body, a Matrix session of its own — comes from the
+ * host instead, or is confined to the container it is mounted in.
+ */
+
+// The element defaults and custom properties every Element Call stylesheet
+// builds on. Written for a page, they speak of `html`, `body` and bare
+// elements; the component build confines them, and every other stylesheet in
+// this bundle, to the root element below (see build/scopeStylesToRoot.ts), so
+// that the host's document is left as it was.
+//
+// Compound is not in here. The component uses the host's copy of it (a peer
+// dependency, left external by the build), and the host loads Compound's
+// stylesheet, design tokens and fonts along with it: what Compound floats into
+// the host's body — tooltips, menus — is then styled by the same stylesheet as
+// everything else there, and Element Call's root takes the tokens and fonts of
+// the theme class it carries, as any element on the host's page would.
+//
+// Where these land relative to the component stylesheets is the bundler's
+// choice — the standalone app puts them first, this build puts them in the
+// middle — so nothing in base.css may depend on winning or losing against a
+// component's own rules at equal specificity. It currently does not: what it
+// declares unlayered is custom properties on Element Call's root, which
+// components inherit rather than compete with.
+import "../src/base.css";
+
+import {
+  type FC,
+  type JSX,
+  type ReactNode,
+  useEffect,
+  useLayoutEffect,
+  useMemo,
+  useRef,
+  useState,
+} from "react";
+import { logger } from "matrix-js-sdk/lib/logger";
+import { I18nextProvider } from "react-i18next";
+import { TooltipProvider } from "@vector-im/compound-web";
+import { ErrorBoundary } from "@sentry/react";
+import { shouldPolyfill as shouldPolyfillSegmenter } from "@formatjs/intl-segmenter/should-polyfill";
+import { shouldPolyfill as shouldPolyfillDurationFormat } from "@formatjs/intl-durationformat/should-polyfill.js";
+
+import LanguageDetector from "i18next-browser-languagedetector";
+
+import EN from "../locales/en/app.json";
+import { CallView } from "../src/room/CallView";
+import { ErrorPage } from "../src/FullScreenView";
+import { ClientProvider } from "../src/ClientContext";
+import { HostBridgeProvider } from "../src/HostBridge";
+import { RootElementProvider, useRootElement } from "../src/RootElementContext";
+import {
+  configurationForIntent,
+  componentProperties,
+  type UrlParams,
+  UrlParamsProvider,
+  UserIntent,
+  useUrlParams,
+} from "../src/UrlParams";
+import { MediaDevicesContext } from "../src/MediaDevicesContext";
+import { MediaDevices } from "../src/state/MediaDevices";
+import { ObservableScope } from "../src/state/ObservableScope";
+import { ProcessorProvider } from "../src/tracks/TrackProcessorContext";
+import { Config } from "../src/config/Config";
+import { type ConfigOptions } from "../src/config/ConfigOptions";
+import { i18n } from "../src/utils/i18n";
+import { useTheme } from "../src/useTheme";
+import { useStableValue } from "../src/useStableValue";
+import styles from "./ElementCall.module.css";
+import { useComponentHostBridge } from "./host";
+import { CallPortalRoot } from "./CallPortalRoot";
+import { type ElementCallProps } from "./api";
+import { supportedLanguages, translationsBackend } from "./localization";
+
+// The languages Element Call can be shown in
+export { supportedLanguages } from "./localization";
+// Everything a host needs to talk about Element Call — the props, the handle,
+// the host bridge, the intents and what each means — also available without
+// the component itself from `@element-hq/element-call-component/api`
+export * from "./api";
+
+/**
+ * Prepares the things Element Call needs before it can be shown: translations,
+ * `Intl` polyfills for older browsers, and its configuration.
+ *
+ * Await this once, before rendering {@link ElementCall}.
+ */
+export async function initializeElementCall(
+  config: ConfigOptions = {},
+): Promise<void> {
+  const polyfills: Promise<unknown>[] = [];
+  if (shouldPolyfillSegmenter())
+    polyfills.push(import("@formatjs/intl-segmenter/polyfill-force"));
+  if (shouldPolyfillDurationFormat())
+    polyfills.push(import("@formatjs/intl-durationformat/polyfill-force.js"));
+  await Promise.all(polyfills);
+
+  Config.initWith(config);
+  await i18n
+    .use(translationsBackend)
+    .use(new LanguageDetector())
+    .init({
+      fallbackLng: "en",
+      defaultNS: "app",
+      keySeparator: ".",
+      nsSeparator: false,
+      pluralSeparator: "_",
+      contextSeparator: "|",
+      supportedLngs: [...supportedLanguages],
+      interpolation: { escapeValue: false },
+      // English is bundled in, so the fallback never has to be loaded; every
+      // other language arrives from the backend when first asked for.
+      partialBundledLanguages: true,
+      resources: { en: { app: EN } },
+      detection: {
+        // The browser's language, until the host says otherwise through the
+        // `language` prop. Nothing is remembered: the choice is the host's.
+        order: ["navigator"],
+        caches: [],
+      },
+    });
+}
+
+/** Applies the theme and background to the container, before it is painted. */
+const Decoration: FC<{ children: JSX.Element }> = ({ children }) => {
+  useTheme();
+  const { background } = useUrlParams();
+  const rootElement = useRootElement();
+  useLayoutEffect(() => {
+    rootElement.setAttribute("data-background", background);
+  }, [rootElement, background]);
+  return children;
+};
+
+export const ElementCall: FC<ElementCallProps> = ({
+  client,
+  roomId,
+  intent = UserIntent.JoinExistingCall,
+  config,
+  hostBridge: suppliedHostBridge,
+  ref,
+  theme,
+  language,
+  portalRoot,
+}): ReactNode => {
+  const hostBridge = useComponentHostBridge(suppliedHostBridge, ref, theme);
+
+  useEffect(() => {
+    if (language !== undefined)
+      i18n
+        .changeLanguage(language)
+        .catch((e) => logger.error(`Could not switch to ${language}`, e));
+  }, [language]);
+
+  // The container is what Element Call decorates and portals into, so nothing
+  // inside can render until we have it.
+  const [container, setContainer] = useState<HTMLDivElement | null>(null);
+
+  // Element Call has no URL of its own to read any of this from, and the
+  // host's URL is not Element Call's business, so the defaults come from the
+  // intent with the host's wishes over the top.
+  //
+  // Everything downstream — the mute state, the call view model and with it
+  // the media connection — is keyed on the identity of this object, so it has
+  // to be stable for as long as its contents are. A host writing `config`
+  // inline would otherwise tear the call down on every render.
+  const stableConfig = useStableValue(config);
+  const params = useMemo(
+    (): UrlParams => ({
+      ...componentProperties,
+      roomId,
+      ...configurationForIntent(intent),
+      ...stableConfig,
+    }),
+    [roomId, intent, stableConfig],
+  );
+
+  // Created in an effect so that the scope it lives in ends when the component
+  // is unmounted (or these options change), rather than keeping its device
+  // observers running for the rest of the page's life. Null until then, which
+  // is one render.
+  const { controlledAudioDevices, callIntent } = params;
+  const [mediaDevices, setMediaDevices] = useState<MediaDevices | null>(null);
+  useEffect(() => {
+    const scope = new ObservableScope();
+    setMediaDevices(
+      new MediaDevices(scope, { controlledAudioDevices, callIntent }),
+    );
+    return (): void => {
+      setMediaDevices(null);
+      scope.end();
+    };
+  }, [controlledAudioDevices, callIntent]);
+
+  const room = client.getRoom(roomId);
+  const rtcSession = useMemo(
+    () => (room === null ? null : client.matrixRTC.getRoomSession(room)),
+    [client, room],
+  );
+
+  if (rtcSession === null)
+    logger.error(
+      `Element Call was asked to call in ${roomId}, which its host's client does not know about`,
+    );
+
+  // Everything the call needs is in hand once these exist, and the first
+  // render with them is where the call itself appears: the moment the host
+  // is told that Element Call has loaded, as the widget tells its client once
+  // its own initialisation is over. Once per mount, however often the pieces
+  // are later swapped out.
+  const ready =
+    container !== null && rtcSession !== null && mediaDevices !== null;
+  const announcedLoaded = useRef(false);
+  useEffect(() => {
+    if (!ready || announcedLoaded.current) return;
+    announcedLoaded.current = true;
+    hostBridge
+      .contentLoaded()
+      .catch((e) => logger.error("Could not tell the host we had loaded", e));
+  }, [ready, hostBridge]);
+
+  return (
+    <I18nextProvider i18n={i18n}>
+      <HostBridgeProvider value={hostBridge}>
+        <UrlParamsProvider value={params}>
+          <div ref={setContainer} className={styles.root}>
+            {ready && (
+              // Stands in for the standalone page's `#root`: see `.content`
+              // in ElementCall.module.css
+              <div className={styles.content}>
+                <CallPortalRoot root={portalRoot}>
+                  <RootElementProvider value={container}>
+                    {/* Whatever goes wrong in here is shown in here. Left to
+                    propagate, an error would unmount the host's own tree. */}
+                    <ErrorBoundary
+                      fallback={(error) => <ErrorPage error={error} />}
+                      // A broken call should not hold the host on screen
+                      onError={() => void hostBridge.setAlwaysOnScreen(false)}
+                    >
+                      <Decoration>
+                        <TooltipProvider>
+                          <ClientProvider client={client}>
+                            <MediaDevicesContext value={mediaDevices}>
+                              <ProcessorProvider>
+                                <CallView
+                                  client={client}
+                                  rtcSession={rtcSession}
+                                  isPasswordlessUser={false}
+                                  confineToRoom={params.confineToRoom}
+                                  preload={params.preload}
+                                  skipLobby={params.skipLobby}
+                                />
+                              </ProcessorProvider>
+                            </MediaDevicesContext>
+                          </ClientProvider>
+                        </TooltipProvider>
+                      </Decoration>
+                    </ErrorBoundary>
+                  </RootElementProvider>
+                </CallPortalRoot>
+              </div>
+            )}
+          </div>
+        </UrlParamsProvider>
+      </HostBridgeProvider>
+    </I18nextProvider>
+  );
+};

component/localization.test.ts

@@ -0,0 +1,46 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { describe, expect, test } from "vitest";
+
+import { supportedLanguages, translationsBackend } from "./localization";
+
+const read = async (
+  language: string,
+  namespace = "app",
+): Promise<Record<string, unknown>> =>
+  await new Promise((resolve, reject) =>
+    translationsBackend.read(language, namespace, (error, data) => {
+      if (error) reject(error);
+      else resolve(data as Record<string, unknown>);
+    }),
+  );
+
+describe("component translations", () => {
+  test("offer every language in locales/, tagged as its directory is", () => {
+    expect(supportedLanguages).toContain("en");
+    expect(supportedLanguages).toContain("de");
+    expect(supportedLanguages).toContain("zh-Hans");
+    expect(new Set(supportedLanguages).size).toBe(supportedLanguages.length);
+  });
+
+  test("load a language's translations on demand", async () => {
+    const de = await read("de");
+    expect(de).toHaveProperty("action");
+    expect(de).not.toEqual(await read("en"));
+  });
+
+  test("refuse a language there are no translations for", async () => {
+    await expect(read("xx")).rejects.toThrow("No app translations for xx");
+  });
+
+  test("refuse a namespace there are no translations for", async () => {
+    await expect(read("en", "other")).rejects.toThrow(
+      "No other translations for en",
+    );
+  });
+});

component/localization.ts

@@ -0,0 +1,55 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+/**
+ * Translations for Element Call as a component.
+ *
+ * The standalone app fetches its locale files at runtime from URLs its own
+ * build emits, which a host serving the library from somewhere else could not
+ * resolve. The component instead has the bundler split every locale into a
+ * chunk of its own, loaded the first time its language is asked for; English,
+ * the fallback, is bundled in so that the first paint never waits for it.
+ */
+
+import { type BackendModule, type ResourceKey } from "i18next";
+
+import { languageOfLocalePath } from "../src/utils/i18n";
+
+/** Every locale, as a lazily imported module. */
+const translations = import.meta.glob<{ default: ResourceKey }>(
+  "../locales/*/app.json",
+);
+
+/**
+ * The languages Element Call can be shown in, as BCP 47 tags — `en`, `de`,
+ * `zh-Hans` and so on. A language that is not one of these falls back to its
+ * base language where there is one (`de-AT` to `de`), and to English otherwise.
+ */
+export const supportedLanguages: readonly string[] = [
+  ...new Set(Object.keys(translations).map(languageOfLocalePath)),
+];
+
+/** Loads translations on demand. */
+export const translationsBackend: BackendModule = {
+  type: "backend",
+  init(): void {},
+  read(language: string, namespace: string, callback): void {
+    const load = translations[`../locales/${language}/${namespace}.json`];
+    if (load === undefined) {
+      callback(new Error(`No ${namespace} translations for ${language}`), null);
+      return;
+    }
+    load().then(
+      (module) => callback(null, module.default),
+      (error: unknown) =>
+        callback(
+          error instanceof Error ? error : new Error(String(error)),
+          null,
+        ),
+    );
+  },
+};

component/package.json

@@ -0,0 +1,47 @@
+{
+  "name": "@element-hq/element-call-component",
+  "version": "0.0.0",
+  "description": "Element Call as a React component. Consumed straight from the repository as a git dependency (github:element-hq/element-call#<ref>&path:/component): the host's package manager runs `prepare`, which builds `dist/`.",
+  "license": "SEE LICENSE IN ../README.md",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/element-hq/element-call",
+    "directory": "component"
+  },
+  "type": "module",
+  "devEngines": {
+    "packageManager": {
+      "name": "pnpm"
+    }
+  },
+  "files": [
+    "dist"
+  ],
+  "main": "./dist/element-call.js",
+  "module": "./dist/element-call.js",
+  "types": "./dist/types/component/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/types/component/index.d.ts",
+      "default": "./dist/element-call.js"
+    },
+    "./api": {
+      "types": "./dist/types/component/api.d.ts",
+      "default": "./dist/api.js"
+    },
+    "./style.css": "./dist/element-call.css"
+  },
+  "sideEffects": [
+    "*.css"
+  ],
+  "scripts": {
+    "prepare": "cd .. && pnpm install --frozen-lockfile && pnpm build:component"
+  },
+  "peerDependencies": {
+    "@vector-im/compound-design-tokens": "^11.0.0",
+    "@vector-im/compound-web": "^10.3.1",
+    "matrix-js-sdk": "*",
+    "react": "^19",
+    "react-dom": "^19"
+  }
+}

component/pnpm-lock.yaml

@@ -0,0 +1,9 @@
+lockfileVersion: '9.0'
+
+settings:
+  autoInstallPeers: false
+  excludeLinksFromLockfile: false
+
+importers:
+
+  .: {}

component/pnpm-workspace.yaml

@@ -0,0 +1,14 @@
+# Makes `component/` a pnpm project of its own rather than a directory inside
+# the repository's workspace. That matters when a host installs the component
+# straight from this repository (`github:element-hq/element-call#…&path:/component`):
+# pnpm prepares such a dependency by running `pnpm install` in this directory,
+# and only a project root gets its `prepare` script (see package.json) run, which
+# is what builds `dist/`. Inside the repository's own workspace the install
+# would silently target the repository instead and build nothing.
+#
+# Consequence for development: pnpm commands run from within this directory see
+# this project, not the repository; run them from the repository root.
+
+# Nothing to install here: the peers in package.json are the host's, and the
+# build runs against the repository's own node_modules (see `prepare`).
+autoInstallPeers: false

component/tsconfig.build.json

@@ -0,0 +1,20 @@
+{
+  // Declaration output for the component package (`pnpm build:component:types`).
+  // The root tsconfig only type-checks; this one emits `.d.ts` files, and nothing
+  // else, for everything the component's entry point reaches. The layout under
+  // `dist/types` mirrors the repository (`component/index.d.ts`, `src/…`), which
+  // is what `package.json` points its `types` at.
+  "extends": "../tsconfig.json",
+  "compilerOptions": {
+    "noEmit": false,
+    "emitDeclarationOnly": true,
+    "declaration": true,
+    "declarationMap": false,
+    "rootDir": "..",
+    "outDir": "./dist/types"
+  },
+  // The entry points, plus the ambient declarations (CSS modules, `?react` SVGs,
+  // `import.meta.env`, …) that the sources they reach rely on.
+  "include": ["./index.tsx", "./api.ts", "../src/@types/*.d.ts"],
+  "exclude": []
+}

config/config.devenv.json

@@ -5,15 +5,9 @@
       "server_name": "synapse.m.localhost"
     }
   },
-  "features": {
-    "feature_use_device_session_member_events": true
-  },
   "ssla": "https://static.element.io/legal/element-software-and-services-license-agreement-uk-1.pdf",
   "matrix_rtc_session": {
-    "wait_for_key_rotation_ms": 3000,
     "membership_event_expiry_ms": 180000000,
-    "delayed_leave_event_delay_ms": 18000,
-    "delayed_leave_event_restart_ms": 4000,
     "network_error_retry_ms": 100
   }
 }

config/config.sample.json

@@ -8,16 +8,10 @@
   "livekit": {
     "livekit_service_url": "https://livekit-jwt.mydomain.com"
   },
-  "features": {
-    "feature_use_device_session_member_events": true
-  },
   "ssla": "https://static.element.io/legal/element-software-and-services-license-agreement-uk-1.pdf",
-  "matrix_rtc_mode": "legacy",
+  "matrix_rtc_mode": "compatibility",
   "matrix_rtc_session": {
-    "wait_for_key_rotation_ms": 3000,
     "membership_event_expiry_ms": 180000000,
-    "delayed_leave_event_delay_ms": 18000,
-    "delayed_leave_event_restart_ms": 4000,
     "network_error_retry_ms": 100
   }
 }

config/config_netlify_preview.json

@@ -7,10 +7,7 @@
   },
   "ssla": "https://static.element.io/legal/element-software-and-services-license-agreement-uk-1.pdf",
   "matrix_rtc_session": {
-    "wait_for_key_rotation_ms": 3000,
     "membership_event_expiry_ms": 180000000,
-    "delayed_leave_event_delay_ms": 18000,
-    "delayed_leave_event_restart_ms": 4000,
     "network_error_retry_ms": 100
   },
   "posthog": {

config/config_netlify_preview_sdk.json

@@ -7,10 +7,7 @@
   },
   "ssla": "https://static.element.io/legal/element-software-and-services-license-agreement-uk-1.pdf",
   "matrix_rtc_session": {
-    "wait_for_key_rotation_ms": 3000,
     "membership_event_expiry_ms": 180000000,
-    "delayed_leave_event_delay_ms": 18000,
-    "delayed_leave_event_restart_ms": 4000,
     "network_error_retry_ms": 100
   }
 }

docker-compose-dev.yml

@@ -3,7 +3,7 @@ networks:
 
 services:
   auth-service:
-    image: ghcr.io/element-hq/lk-jwt-service:0.4.4
+    image: ghcr.io/element-hq/lk-jwt-service:0.8.0
     pull_policy: always
     hostname: auth-server
     environment:
@@ -15,6 +15,14 @@ services:
       # a self-signed certificate
       - LIVEKIT_INSECURE_SKIP_VERIFY_TLS=YES_I_KNOW_WHAT_I_AM_DOING
       - LIVEKIT_FULL_ACCESS_HOMESERVERS=*
+      # Registers this instance as an application service on the main homeserver
+      - LIVEKIT_AS_REGISTRATION_FILE=/etc/lk-jwt-service/app-service.yaml
+      - LIVEKIT_HS_SERVER_NAME=synapse.m.localhost
+      # Neither homeserver serves /.well-known/matrix/client, so the C-S API
+      # location has to be given explicitly.
+      - LIVEKIT_CS_API_URL_OVERRIDES=synapse.m.localhost=http://homeserver:8008,synapse.othersite.m.localhost=http://homeserver-1:18008
+    volumes:
+      - ./backend/app-service.yaml:/etc/lk-jwt-service/app-service.yaml:Z
     deploy:
       restart_policy:
         condition: on-failure
@@ -25,7 +33,7 @@ services:
       - ecbackend
 
   auth-service-1:
-    image: ghcr.io/element-hq/lk-jwt-service:0.4.4
+    image: ghcr.io/element-hq/lk-jwt-service:0.8.0
     pull_policy: always
     hostname: auth-server-1
     environment:
@@ -37,6 +45,14 @@ services:
       # a self-signed certificate
       - LIVEKIT_INSECURE_SKIP_VERIFY_TLS=YES_I_KNOW_WHAT_I_AM_DOING
       - LIVEKIT_FULL_ACCESS_HOMESERVERS=*
+      # Registers this instance as an application service on the other homeserver.
+      - LIVEKIT_AS_REGISTRATION_FILE=/etc/lk-jwt-service/app-service.yaml
+      - LIVEKIT_HS_SERVER_NAME=synapse.othersite.m.localhost
+      # Neither homeserver serves /.well-known/matrix/client, so the C-S API
+      # location has to be given explicitly.
+      - LIVEKIT_CS_API_URL_OVERRIDES=synapse.m.localhost=http://homeserver:8008,synapse.othersite.m.localhost=http://homeserver-1:18008
+    volumes:
+      - ./backend/app-service-othersite.yaml:/etc/lk-jwt-service/app-service.yaml:Z
     deploy:
       restart_policy:
         condition: on-failure
@@ -47,7 +63,7 @@ services:
       - ecbackend
 
   livekit:
-    image: livekit/livekit-server:v1.10.1
+    image: livekit/livekit-server:v1.13.4
     pull_policy: always
     hostname: livekit-sfu
     command: --dev --config /etc/livekit.yaml
@@ -70,7 +86,7 @@ services:
       - ecbackend
 
   livekit-1:
-    image: livekit/livekit-server:v1.10.1
+    image: livekit/livekit-server:v1.13.4
     pull_policy: always
     hostname: livekit-sfu-1
     command: --dev --config /etc/livekit.yaml
@@ -94,7 +110,10 @@ services:
 
   synapse:
     hostname: homeserver
-    image: ghcr.io/element-hq/synapse:latest
+    # develop (not latest) is required for application service C-S/S-S proxying
+    # (MSC4512) and membership look-ups (MSC4502), which are not in a stable
+    # release yet.
+    image: ghcr.io/element-hq/synapse:develop
     pull_policy: always
     environment:
       - SYNAPSE_CONFIG_PATH=/data/cfg/homeserver.yaml
@@ -107,12 +126,16 @@ services:
     volumes:
       - ./backend/synapse_tmp:/data:Z
       - ./backend/dev_homeserver.yaml:/data/cfg/homeserver.yaml:Z
+      - ./backend/app-service.yaml:/data/cfg/app-service.yaml:Z
     networks:
       - ecbackend
 
   synapse-1:
     hostname: homeserver-1
-    image: ghcr.io/element-hq/synapse:latest
+    # develop (not latest) is required for application service C-S/S-S proxying
+    # (MSC4512) and membership look-ups (MSC4502), which are not in a stable
+    # release yet.
+    image: ghcr.io/element-hq/synapse:develop
     pull_policy: always
     environment:
       - SYNAPSE_CONFIG_PATH=/data/cfg/homeserver.yaml
@@ -125,6 +148,7 @@ services:
     volumes:
       - ./backend/synapse_tmp_othersite:/data:Z
       - ./backend/dev_homeserver-othersite.yaml:/data/cfg/homeserver.yaml:Z
+      - ./backend/app-service-othersite.yaml:/data/cfg/app-service.yaml:Z
     networks:
       - ecbackend
 
@@ -156,7 +180,7 @@ services:
   nginx:
     #  see backend/dev_tls_setup for how to generate the tls certs
     hostname: synapse.m.localhost
-    image: nginx:latest
+    image: nginx:latest@sha256:4ae259ae64fbedb67918c07d167fdcb0e05855a1615480ca445bea485e7d65ff
     pull_policy: always
     volumes:
       - ./backend/dev_nginx.conf:/etc/nginx/conf.d/default.conf:Z

docker-compose-playwright.yml

@@ -0,0 +1,25 @@
+# This file contains overrides to docker-compose-dev.yml and should
+# only be used in combination with that file.
+services:
+  synapse:
+    # Pin to a SHA so that upstream cannot break our tests. Renovate handles regular updates.
+    # develop (not latest) is required for application service C-S/S-S proxying
+    # (MSC4512) and membership look-ups (MSC4502), which are not in a stable
+    # release yet.
+    image: ghcr.io/element-hq/synapse:develop@sha256:337921fd22be310d453344b2265f6c9942315446595df3cf81866f71ca2055a7
+    volumes:
+      - ./backend/playwright_homeserver.yaml:/data/cfg/homeserver.yaml:Z
+  synapse-1:
+    # Pin to a SHA so that upstream cannot break our tests. Renovate handles regular updates.
+    # develop (not latest) is required for application service C-S/S-S proxying
+    # (MSC4512) and membership look-ups (MSC4502), which are not in a stable
+    # release yet.
+    image: ghcr.io/element-hq/synapse:develop@sha256:337921fd22be310d453344b2265f6c9942315446595df3cf81866f71ca2055a7
+    volumes:
+      - ./backend/playwright_homeserver-othersite.yaml:/data/cfg/homeserver.yaml:Z
+  element-web:
+    # Pin to a SHA so that upstream cannot break our tests. Renovate handles regular updates.
+    image: ghcr.io/element-hq/element-web:develop@sha256:b2a5a30afb4f583a7560448b005d8332bee29672f15826e4a995b393058f0291
+  element-web-1:
+    # Pin to a SHA so that upstream cannot break our tests. Renovate handles regular updates.
+    image: ghcr.io/element-hq/element-web:develop@sha256:b2a5a30afb4f583a7560448b005d8332bee29672f15826e4a995b393058f0291

docs/README.md

@@ -3,7 +3,18 @@
 This folder contains documentation for setup, usage, and development of Element Call.
 
 - [Embedded vs standalone mode](./embedded_standalone.md)
+- [Element Call as a React component (experimental)](../README.md#element-call-as-a-component-experimental)
 - [Url format and parameters](./url_params.md)
 - [Global JS controls](./controls.md)
+- [MatrixRTC modes](./matrix_rtc_modes.md)
 - [Self-Hosting](./self_hosting.md)
 - [Developing with linked packages](./linking.md)
+
+### Writing code for Element Call (agent-readable conventions)
+
+Entry point: [AGENTS.md](../AGENTS.md).
+
+- [Agent workflow](./agents/workflow.md)
+- [Architecture](./agents/architecture.md)
+- [Code style](./agents/code-style.md)
+- [Testing](./agents/testing.md)

docs/agents/architecture.md

@@ -0,0 +1,95 @@
+# Architecture
+
+## Logic lives in view models; components render
+
+- Call logic lives in `src/state/`. A component that derives call state is
+  misplaced logic.
+- Composing behaviors: a factory taking `(scope, ...deps$)`, returning named
+  behaviors plus callbacks. Copy `src/state/LayoutSwitchViewModel.ts`. Prefer this
+  for anything new.
+- Owning a resource: a class taking the scope in its constructor — `MediaDevices`,
+  `MuteStates`, `TileStore`, `Publisher`, `Connection`. Both styles are current;
+  don't convert one to the other in passing.
+- `foo$` is an observable. `Behavior<T>`, an observable with a current value, is
+  the default for anything a view reads.
+
+## The view model / view contract
+
+- Components take `vm: ViewModel<Snapshot>` and read state through `useBehavior`.
+  See `CallFooter`, `InCallView`, `LobbyView`, `SettingsModal`.
+- A snapshot is `Actions & State`; every field becomes a `foo$` behavior, and none
+  is optional.
+- An unavailable action is `undefined`, not a separate `canDoThing` flag — the
+  presence of the callback drives the rendering.
+- Subscribe in an effect only to drive a side effect off an event stream, as
+  `ReactionAudioRenderer` does; never to read state a behavior already holds.
+
+## Scopes own lifetimes
+
+- `ObservableScope` bounds every subscription a view model creates.
+- Reference only the scope defined in the same function; one captured from an
+  enclosing scope outlives its owner, and `no-observablescope-leak` rejects it.
+
+## Nothing reads the page
+
+Element Call can be mounted several times inside a host's React tree, so it owns
+neither window, URL, document nor router. Each seam defaults to the old standalone
+and widget behaviour.
+
+| Never                                         | Use                                                           |
+| --------------------------------------------- | ------------------------------------------------------------- |
+| the `widget` global                           | `useHostBridge()` — `src/HostBridge.ts`                       |
+| `getUrlParams()`, `window.location`           | `useUrlParams()`                                              |
+| `useNavigate("/")`, `<Link to="/">`           | `useLeaveToHome()`, `LeaveToHomeLink`                         |
+| `document.body`                               | `useRootElement()`                                            |
+| `window.innerWidth/Height`, `useMediaQuery`   | `useRootSizeMatches()` in views, `windowSize$` in view models |
+| global `i18next`                              | the instance in `src/utils/i18n.ts`                           |
+| config or analytics reading their environment | `Config.initWith()`, `PosthogAnalytics.configure()`           |
+
+- View models take values as options, never `getUrlParams()`
+  (`callViewModelOptionsFromParams`, `CallViewModelOptions.hostBridge`).
+- The host bridge is the only channel to the host: `createWidgetHostBridge(widget)`,
+  `nullHostBridge` standalone, `useComponentHostBridge`. State a capability
+  (`supportsReactions`, `supportsProfileChanges`); never infer it from being a
+  widget.
+- Shortcuts and portals attach to the root element, so two instances don't fight.
+- Known debt, not precedent: `Grid` measures `window.innerHeight`; `ErrorView`'s
+  reload and `getAbsoluteRoomUrl` use `window.location`; recaptcha appends to
+  `document.body` on the standalone login path.
+
+## Context differences are options, not checks
+
+- Named options with per-intent defaults (`configurationForIntent`), never a
+  runtime check for who is hosting.
+- `controlledAudioDevices`, not the platform, is what makes `MediaDevices` pick
+  `AndroidControlledAudioOutput` / `IOSControlledAudioOutput` over the web
+  `AudioOutput`. Intent presets set it on non-desktop; standalone leaves it off.
+- URL params are a published contract: change one, update `docs/url_params.md`.
+
+## Build targets
+
+Code that builds in only one is a bug.
+
+- `build:full` — standalone app, also widget mode.
+- `build:embedded` — `@element-hq/element-call-embedded`.
+- `build:sdk` — `@element-hq/matrixrtc-sdk`, sources in `sdk/`, entry `sdk/index.ts`.
+  Packaged exactly like the component (own pnpm project, run pnpm from the repo
+  root, types from `sdk/tsconfig.build.json`, externals checked by
+  `pnpm lint:externals`). Interface only so far; the design is `sdk-plan.md`.
+- `build:sdk-target-based-on-call-view-model` — the SDK demo that predates the
+  package, one bundle of the `CallViewModel`; entry
+  `sdk-target-based-on-call-view-model/main.ts`. CI's `sdk` package
+  (`build:sdk:production` / `build:sdk:development`, the Netlify `-sdk` preview)
+  is still this bundle, not `build:sdk`.
+- `build:component` — `@element-hq/element-call-component`, sources in `component/`
+  (its own pnpm project; run pnpm from the repo root). Host API is in the README;
+  `pnpm lint:externals` rejects an import of a `react` / `react-dom` /
+  `matrix-js-sdk` / `@vector-im/compound-web` /
+  `@vector-im/compound-design-tokens` subpath the externals list omits.
+  `livekit-client` is bundled on purpose: no host imports it, and the pinned
+  version travels with the component.
+  Compound's stylesheets are loaded by `src/index.css` for the page and by the
+  host for the component, never by `src/base.css`. Two entry
+  points: `index.tsx` (the component) and `api.ts` (types, enums and
+  `configurationForIntent`, for a host that must not load the component). `api.ts`
+  may only reach types and constants — `src/UrlConfiguration.ts`, not `UrlParams`.

docs/agents/code-style.md

@@ -0,0 +1,95 @@
+# Code style
+
+_Clean Code_ (Robert C. Martin): small functions, intention-revealing names, low
+noise.
+
+## Reuse before you build
+
+Look before you write, in this order:
+
+1. **Compound Web** — `@vector-im/compound-web` for buttons, tooltips, alerts,
+   dialogs, menus, form controls, avatars; icons in
+   `@vector-im/compound-design-tokens/assets/web/icons`.
+2. **This repo** — `src/button/`, `src/components/`, `src/input/`, `src/form/`,
+   `src/tabs/`, and `Modal`, `Avatar`, `Toast`, `Slider`, `ErrorView`,
+   `FullScreenView` at the root of `src/`.
+3. **The nearest existing feature** — grep for the same shape first. A hook is
+   often what you want to extract, not a component.
+
+If nothing fits, name the new shared component in the PR body and say what you
+rejected and why — never add one silently. Extend or parameterise before forking,
+and extract shared logic into a hook both callers use before copying it; if you
+copy, the PR says so.
+
+## Ordering
+
+- **Newspaper order.** Headline first, detail down. A file opens with what it
+  exists to provide.
+- **Stepdown rule.** Caller above callee. A helper used by one function sits
+  beneath it, which needs a `function` declaration, not a `const` arrow. Existing
+  arrow components above their callers are not a pattern to extend — nor to churn.
+- **Suites.** Test cases first, helpers below. Older suites invert this; follow the
+  rule in new ones, don't reorder old ones.
+- **Names.** What a thing means, not what it is made of: `naturalLayout$`, not
+  `computedLayout$`.
+
+## Comments
+
+No comment is the default. One earns its place by giving a reason the code
+cannot: a platform quirk, an outside constraint, a trap that looks like a
+simplification.
+
+- Say the reason, then stop. Test each sentence: does the reason still stand
+  without it? If so, cut it. Most reasons fit on a line, so a long comment is
+  worth a second look — it is usually carrying something that isn't one.
+- Write about the line the comment sits on, in terms of what the code does
+  there — leave layout to the stylesheet and measurements to the design.
+- Name the condition ("where the platform can't route audio"), not the browser
+  or the spec entry.
+- Put history — what was tried, removed or rejected, the dev journal — in the
+  commit or the PR description.
+- In tests, comment only structure that looks wrong but isn't: batching, timers,
+  why this scroll position.
+
+Before keeping one: would it still be true after a CSS change or a refactor of
+its caller? If not, cut it.
+
+## TypeScript, React and RxJS idiom win on a clash
+
+- Hooks stay unconditional at the top of a component.
+- `useCallback` / `useMemo` dependency arrays sometimes force inlining.
+- An RxJS pipeline stays one expression. Name the behavior, not each operator.
+- A long factory is fine when it reads as a list of named behaviors.
+  `CallViewModel.ts` is long because the domain is.
+- Marble test tables are dense on purpose.
+
+## Enforced by lint
+
+- Copyright header on every file: `Copyright <current year> Element Creations Ltd.`
+  plus the AGPL / commercial SPDX line.
+- `logger` from `matrix-js-sdk/lib/logger`, never `console`, and no top-level
+  `logger.getChild()`. The `console` ban is only enforced under `src/*/**`.
+- No floating or misused promises; async functions typed `Promise<T>`.
+- Inline type imports (`import { type Foo }`), so matrix-js-sdk stays lazily
+  loadable.
+- Deep-import `matrix-js-sdk/lib/<module>` as the codebase does. Banned is the bare
+  `matrix-js-sdk/lib`, `lib/index` and anything under `src/`.
+
+## CSS
+
+- Compound components and `--cpd-*` tokens in CSS modules. A hardcoded colour or px
+  spacing is a design question, not a licence to inline a hex.
+- Size against the root, not the window: `@container element-call (…)` and
+  `cqw` / `cqh`, never `@media (width)` or `vw` / `vh`. Media queries stay correct
+  only in standalone-only views — home, login.
+- Style `[data-element-call-root]`, never `body` or `:root`; the component build
+  makes those stand for the root (`component/build/scopeStylesToRoot.ts`).
+
+## Strings and a11y
+
+- Strings through `t()`: add the key, run `pnpm i18n`, fill `locales/en/app.json`.
+  Other locales come from Localazy; never hand-edit them.
+- `t` from `useTranslation()`, or `src/utils/i18n.ts` outside React. Never the
+  `i18next` global — several instances share a page.
+- Accessible names on controls, `aria-pressed` on toggles, keyboard reachability.
+  `jsx-a11y` rules are errors; `vitest-axe` is available.

docs/agents/testing.md

@@ -0,0 +1,57 @@
+# Testing
+
+Three layers; a user-facing feature needs all three. Unit proves the logic,
+Storybook proves the rendering, e2e proves the feature. Codecov gates 80% on the
+lines a PR touches.
+
+## Unit
+
+- View model tests use `withTestScheduler` + `testScope()` from `src/utils/test.ts`
+  and read as ASCII timelines. Copy `LayoutSwitchViewModel.test.ts`.
+- Component tests use Testing Library, queried by role and accessible name.
+- Reuse the factories in `src/utils/test.ts` — `mockRemoteParticipant`,
+  `mockMatrixRoom`, `mockLivekitRoom`, `MockRTCSession`. Hand-rolled mocks drift.
+- Snapshots live in `__snapshots__/`; update with `pnpm test <Name> -u`.
+- How often something redraws is testable: drive the frames and count commits, not
+  render calls. An effect with no dependency array runs once per commit.
+- `component/**/*.test.ts` runs in the same jsdom project as `src`.
+
+## Storybook
+
+A deliverable, not documentation: `pnpm test:storybook` runs every story as a real
+browser test in the same CI job as the unit suite. **A UI change without a story is
+incomplete.** Only three stories exist so far, so copy `CallFooter.stories.tsx`.
+
+- Drive the component from a snapshot via `useStaticViewModel`, never internals.
+- One named story per state that matters — loading, error, empty, denied, mobile.
+- Assert in a `play` function with `userEvent` / `expect` from `storybook/test`.
+- Mobile is `globals: { viewport: { value: "mobile2" } }`, not a second component.
+- Expose interesting props through `argTypes`.
+
+`.storybook/preview.tsx` supplies `TooltipProvider`, `src/index.css` and English
+translations. The browser is Playwright's, so a fresh clone needs
+`pnpm playwright install` once.
+
+## End-to-end
+
+- `playwright/*.spec.ts` — standalone, on Chromium and Firefox.
+- `playwright/widget/` — widget mode, where cross-context bugs surface.
+- `playwright/component/` — the component in a host page, via the harness on port
+  3001 that Playwright starts as a second web server. Catches container-relative
+  layout, styles escaping the root, two instances on a page, host-bridge reports.
+- `playwright/sdk/` — the MatrixRTC SDK through its harness on port 3002, a page
+  with none of Element Call on it. The smoke test is what the implementation is
+  built against.
+- `playwright/mobile/` — Pixel 7, `mobile` project only.
+
+Test what a user observes: the peer sees the change, it survives a reconnect, it is
+right after a reload. Reuse `playwright/spa-helpers.ts`,
+`playwright/widget/test-helpers.ts`, `playwright/fixtures/`.
+
+```sh
+pnpm test                   # unit + storybook
+pnpm backend                # Synapse + LiveKit, required for e2e
+pnpm test:playwright        # or :open
+pnpm dev:component          # component harness, port 3001
+pnpm dev:sdk                # SDK harness, port 3002
+```

docs/agents/workflow.md

@@ -0,0 +1,50 @@
+# Agent workflow
+
+## Scratch files live in `agent-workspace/`
+
+Git-ignored. One kebab-case subfolder per task, matching the branch topic:
+`agent-workspace/<slug>/`.
+
+| File                        | Purpose                                                                          |
+| --------------------------- | -------------------------------------------------------------------------------- |
+| `plan.md`                   | The concrete approach — files, symbols, edit order — once direction is confirmed |
+| `commit-msg.txt`            | `git commit -F agent-workspace/<slug>/commit-msg.txt`                            |
+| `pr-body.md`                | `gh pr create --body-file agent-workspace/<slug>/pr-body.md`                     |
+| `implementation-summary.md` | What was built, decisions, trade-offs                                            |
+| `NN-prompt.md`              | Raw prompt text, numbered, when worth keeping                                    |
+
+- Nothing here is durable. The folder is ignored, so anything worth keeping is
+  promoted into the PR body, a doc, or a feature spec before the task ends.
+- Never write scratch files to the repo root. Stray `load_test_summary.md` and
+  `config.json_` files are what this folder prevents.
+- Start `pr-body.md` from `.github/PULL_REQUEST_TEMPLATE.md` and fill every
+  section.
+- Commit subjects are plain imperative English. No conventional-commits prefixes.
+- A `plan.md` and a feature spec sit at different altitudes; neither replaces the
+  other. A spec in `FEATURES_SPEC/` is durable and deliberately abstract —
+  behaviour, decisions, acceptance criteria — so the feature can be rebuilt against
+  a `main` nobody has seen yet. A plan is one slice of it landing on today's
+  `main`: the paths, symbols and edit order the spec's decisions and criteria must
+  not name. `FEATURES_SPEC/AGENTS.md` wins wherever the two genuinely overlap.
+
+## Hand off before the quality pass
+
+- Implement the change, run the narrowest check that rules out an obviously broken
+  handoff, then stop and ask whether the direction is right.
+- Full `pnpm lint`, the whole suite, coverage and benchmarks come after the
+  direction is confirmed.
+- Wider refactors, extra tests and documentation polish are follow-up work, not
+  part of the first handoff.
+- If a check is needed before feedback, keep it to the touched code and say why.
+
+## Commit and PR readiness
+
+- Commit once the user confirms direction, or asks for one. Not before. Where the
+  setup has no git identity, a sandbox included, write the message to
+  `commit-msg.txt` and hand it over instead.
+- Ready means every gate in [AGENTS.md](../../AGENTS.md#gates) is green and the
+  change is covered at the layers [testing.md](./testing.md) asks for. Read the diff
+  against [code-style.md](./code-style.md) first.
+- Re-run the whole checklist after any fix. Only on green, either way.
+- Once a human has started reviewing, fix forward — never force-push a
+  regeneration over a review in progress.

docs/controls.md

@@ -7,6 +7,9 @@ A few aspects of Element Call's interface can be controlled through a global API
 - `controls.canEnterPip(): boolean` Determines whether it's possible to enter picture-in-picture mode.
 - `controls.enablePip(): void` Puts the call interface into picture-in-picture mode. Throws if not in a call.
 - `controls.disablePip(): void` Takes the call interface out of picture-in-picture mode, restoring it to its natural display mode. Throws if not in a call.
+- `controls.onPipMediaOrientationUpdate: ((orientation: "landscape"|"portrait") => void) | undefined` Callback called whenever the PiP media orientation changes.
+  The client should track this value to already initiate the pip in the right orientation.
+  It should update the orientation of the current Pip window when called.
 
 ## Audio devices
 

docs/embedded_standalone.md

@@ -3,6 +3,9 @@
 Element Call is available as two different packages: Full Package and Embedded Package.
 
 The Full Package is designed for standalone use, while the Embedded Package is designed for widget mode only.
+There is also an experimental third option, a build of Element Call as a React component for applications
+that want to render a call inside their own page rather than in an iframe; see
+[Element Call as a component](../README.md#element-call-as-a-component-experimental) in the README.
 
 The table below provides a comparison of the two packages:
 

docs/linking.md

@@ -60,6 +60,21 @@ git config --local core.hooksPath .githooks
 
 This will add the hook path for this repository only to .gihooks. which is a tracked (by git) folder containing the pre-commit hook.
 
+## Testing against a matrix-js-sdk branch in CI
+
+Linking covers local development. In CI, `scripts/layered.sh` plays the same
+role for `matrix-js-sdk`: after the usual frozen install, `scripts/fetchdep.sh`
+looks for a matrix-js-sdk branch with the same name as the pull request's head
+branch (in the fork first, when the pull request comes from one). If there is
+one, it is cloned, packed and installed over the locked version. If there is
+none, the install stays as `pnpm-lock.yaml` pins it.
+
+This means a change that needs a not yet merged matrix-js-sdk change can be tested
+by giving both branches the same name. This mirrors how element-web tests against
+matrix-js-sdk. Once the matrix-js-sdk branch is merged and deleted, the pull
+request falls back to the lockfile and needs a lockfile bump to stay green,
+which is also what keeps `main` consistent after the merge.
+
 ## Background
 
 Information, why this approach is used can be found in the [linking concept reasoning](./linking_concept_reasoning.md) document.

docs/matrix_rtc_modes.md

@@ -0,0 +1,48 @@
+# MatrixRTC modes
+
+Element Call is in the middle of a transition of how a call session is
+represented: from room _state_ events (`org.matrix.msc3401.call.member`) to
+_sticky_ events
+([MSC4354](https://github.com/matrix-org/matrix-spec-proposals/pull/4354)),
+which are a much better fit for the short lived, per-device nature of call
+memberships.
+
+Not every homeserver supports sticky events yet. The two MatrixRTC modes
+controls whether Element Call uses them.
+
+## The modes
+
+| Mode            | Membership events | SFU selection | JWT endpoint                 |
+| --------------- | ----------------- | ------------- | ---------------------------- |
+| `compatibility` | state events      | multi SFU     | legacy                       |
+| `matrix_2_0`    | sticky events     | multi SFU     | Matrix 2.0 (hashed identity) |
+
+**`compatibility`** — multi SFU, but still state events. Use it when the
+homeserver does not support sticky events. This is the default.
+
+**`matrix_2_0`** — the target state. Requires a homeserver that advertises
+MSC4354 and all clients on v0.17.0 or later. The local membership requests its
+token from the Matrix 2.0 JWT endpoint of the
+[MatrixRTC Authorization Service](https://github.com/element-hq/lk-jwt-service)
+and identifies the room by a hashed identity instead of the Matrix `room_id`.
+(Remote memberships always try the new endpoint first and fall back to the
+legacy one, so remote participants can be on either.)
+
+## Selecting a mode
+
+Users can choose a mode under **Settings → Developer → MatrixRTC mode**. The
+Matrix 2.0 option is disabled if the homeserver does not support sticky events.
+
+A deployment can pin the mode for all its clients in `config.json`, which
+disables the Developer Settings choice:
+
+```json
+{
+  "matrix_rtc_mode": "compatibility"
+}
+```
+
+Valid values are `compatibility` and `matrix_2_0`; an invalid value is
+ignored (with a warning) and the user's choice applies. Pinning `matrix_2_0` on a
+homeserver without sticky event support makes joining fail with a "sticky events
+required" error.

docs/self_hosting.md

@@ -16,7 +16,7 @@
 The following [MSCs](https://github.com/matrix-org/matrix-spec-proposals) are
 required for Element Call to work properly:
 
-- **[MSC3266](https://github.com/deepbluev7/matrix-doc/blob/room-summaries/proposals/3266-room-summary.md):
+- **[MSC3266](https://github.com/deepbluev7/matrix-doc/blob/room-summaries/proposals/3266-room-summary.md)
   Room Summary API**: In Standalone mode Element Call is able to join rooms
   over federation using knocking. In this context MSC3266 is required as it
   allows to request a room summary of rooms you are not joined. The summary
@@ -29,19 +29,26 @@ required for Element Call to work properly:
   signalling. If disabled it is very likely that you end up with stuck calls in
   Matrix rooms.
 
+- **[MSC4519](https://github.com/matrix-org/matrix-spec-proposals/blob/travis/msc/voip-transports-registry/proposals/4519-rtc-transports-registry.md)
+  MatrixRTC Transports Registry**: Defines an endpoint that clients can use to
+  query the available MatrixRTC transports (i.e. find your LiveKit SFU).
+
 - **[MSC4222](https://github.com/matrix-org/matrix-spec-proposals/blob/erikj/sync_v2_state_after/proposals/4222-sync-v2-state-after.md)
   Adding `state_after` to sync v2**: Allow clients to opt-in to a change of the
   sync v2 API that allows them to correctly track the state of the room. This is
   required by Element Call to track room state reliably.
 
 If you're using [Synapse](https://github.com/element-hq/synapse/) as your
-homeserver, you'll need to additionally add the following config items to
-`homeserver.yaml` to comply with Element Call:
+homeserver, you can configure these features by adding the following entries to
+`homeserver.yaml`:
 
 ```yaml
 experimental_features:
   # MSC3266: Room summary API. Used for knocking over federation
   msc3266_enabled: true
+  # MSC4143: MatrixRTC. For historical reasons this flag enables the transports
+  # endpoint defined in MSC4519.
+  msc4143_enabled: true
   # MSC4222 needed for syncv2 state_after. This allow clients to
   # correctly track the state of the room.
   msc4222_enabled: true
@@ -61,6 +68,15 @@ rc_delayed_event_mgmt:
   # Currently the heart-beat is every 5 seconds which translates into a rate of 0.2Hz
   per_second: 1
   burst_count: 20
+
+matrix_rtc:
+  transports:
+    # The transport you specify will be made available to clients over the
+    # /_matrix/client/unstable/org.matrix.msc4143/rtc/transports endpoint as
+    # defined in MSC4519.
+    - type: livekit
+      # Replace this with the actual URL of your MatrixRTC Authorization Service
+      livekit_service_url: https://matrix-rtc.example.com/livekit/jwt
 ```
 
 As a prerequisite for the
@@ -68,10 +84,10 @@ As a prerequisite for the
 make sure that your Synapse server has either a `federation` or `openid`
 [listener configured](https://element-hq.github.io/synapse/latest/usage/configuration/config_documentation.html#listeners).
 
-### MatrixRTC Backend
+### LiveKit backend
 
-In order to **guarantee smooth operation** of Element Call, a MatrixRTC backend is
-required for each site deployment.
+In order to **guarantee smooth operation** of Element Call, a dedicated LiveKit
+backend is required for each site deployment.
 
 ![MSC4195 compatible setup](MSC4195_setup.drawio.png)
 
@@ -86,10 +102,11 @@ to implement
 In the context of MatrixRTC, we suggest using a single hostname for backend
 communication by implementing endpoint routing within a reverse proxy setup. For
 the example above, this results in:
-| Service | Endpoint | Example |
-| -------- | ------- | ------- |
+
+| Service                                                                           | Endpoint       | Example                              |
+| --------------------------------------------------------------------------------- | -------------- | ------------------------------------ |
 | [Livekit SFU](https://github.com/livekit/livekit) WebSocket signalling connection | `/livekit/sfu` | `matrix-rtc.example.com/livekit/sfu` |
-| [MatrixRTC Authorization Service](https://github.com/element-hq/lk-jwt-service) | `/livekit/jwt` | `matrix-rtc.example.com/livekit/jwt` |
+| [MatrixRTC Authorization Service](https://github.com/element-hq/lk-jwt-service)   | `/livekit/jwt` | `matrix-rtc.example.com/livekit/jwt` |
 
 Using Nginx, you can achieve this by:
 
@@ -164,7 +181,7 @@ Using Haproxy, you can achieve this by:
     use_backend mxrtc_auth_backend if is_mxrtc_auth matrixrtc_domain
 
 # Backend
-## MatrixRTC backend
+## LiveKit backend
 backend sfu_backend
     server livekit 127.0.0.1:7880
     http-request set-path %[path,regsub(^/livekit/sfu/,/)]
@@ -186,44 +203,6 @@ backend mxrtc_auth_backend
 
 ```
 
-#### MatrixRTC backend announcement
-
-> [!IMPORTANT]
-> As defined in
-> [MSC4143](https://github.com/matrix-org/matrix-spec-proposals/pull/4143),
-> the MatrixRTC backend(s) must be announced to the client via your **Matrix site's
-> `.well-known/matrix/client`** file (e.g.
-> `example.com/.well-known/matrix/client` matching the site deployment example
-> from above). The configuration is a list of Foci configs:
-
-```json
-"org.matrix.msc4143.rtc_foci": [
-    {
-        "type": "livekit",
-        "livekit_service_url": "https://matrix-rtc.example.com/livekit/jwt"
-    },
-    {
-        "type": "livekit",
-        "livekit_service_url": "https://matrix-rtc-2.example.com/livekit/jwt"
-    }
-]
-```
-
-Make sure this file is served with the correct MIME type (`application/json`).
-Additionally, ensure the appropriate CORS headers are set to allow web clients
-to access it across origins. For more details, refer to the
-[Matrix Client-Server API: 2. Web Browser Clients](https://spec.matrix.org/latest/client-server-api/#web-browser-clients).
-
-```
-Access-Control-Allow-Origin: *
-Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS
-Access-Control-Allow-Headers: X-Requested-With, Content-Type, Authorization
-```
-
-> [!NOTE]  
-> Most `org.matrix.msc4143.rtc_foci` configurations will only have one entry in
-> the array.
-
 ## Building Element Call
 
 > [!NOTE]  
@@ -277,7 +256,7 @@ runtime. Documentation and default values for `public/config.json` can be found
 in [ConfigOptions.ts](../src/config/ConfigOptions.ts).
 
 > [!CAUTION]
-> Please note configuring MatrixRTC backend via `config.json` of
+> Please note configuring LiveKit backend via `config.json` of
 > Element Call is only available for developing and debug purposes. Relying on
 > it might break Element Call going forward!
 

docs/url_params.md

@@ -61,15 +61,15 @@ These parameters are relevant to both [widget](./embedded_standalone.md) and [st
 | `homeserver`                                   |                                                                                                                                                                    | Not applicable                                                                                    | No                           | Homeserver for registering a new (guest) user, configures non-default guest user server when creating a spa link.                                                                                                                                                                                                                                                                                   |
 | `lang`                                         | [BCP 47](https://www.rfc-editor.org/info/bcp47) code                                                                                                               | No                                                                                                | No                           | The language the app should use.                                                                                                                                                                                                                                                                                                                                                                    |
 | `password`                                     |                                                                                                                                                                    | No                                                                                                | No                           | E2EE password when using a shared secret. (For individual sender keys in embedded mode this is not required.)                                                                                                                                                                                                                                                                                       |
-| `perParticipantE2EE`                           | `true` or `false`                                                                                                                                                  | No, defaults to `false`                                                                           | No, defaults to `false`      | Enables per participant encryption with Keys exchanged over encrypted matrix room messages.                                                                                                                                                                                                                                                                                                         |
 | `controlledAudioDevices`                       | `true` or `false`                                                                                                                                                  | No, defaults to `false`                                                                           | No, defaults to `false`      | Whether the [global JS controls for audio devices](./controls.md#audio-devices) should be enabled, allowing the list of audio devices to be controlled by the app hosting Element Call.                                                                                                                                                                                                             |
 | `roomId`                                       | [Matrix Room ID](https://spec.matrix.org/v1.12/appendices/#room-ids)                                                                                               | Yes                                                                                               | No                           | Anything about what room we're pointed to should be from useRoomIdentifier which parses the path and resolves alias with respect to the default server name, however roomId is an exception as we need the room ID in embedded widget mode, and not the room alias (or even the via params because we are not trying to join it). This is also not validated, where it is in `useRoomIdentifier()`. |
 | `showControls`                                 | `true` or `false`                                                                                                                                                  | No, defaults to `true`                                                                            | No, defaults to `true`       | Displays controls like mute, screen-share, invite, and hangup buttons during a call.                                                                                                                                                                                                                                                                                                                |
 | `skipLobby` (deprecated: use `intent` instead) | `true` or `false`                                                                                                                                                  | No. If `intent` is explicitly `start_call` then defaults to `true`. Otherwise defaults to `false` | No, defaults to `false`      | Skips the lobby to join a call directly, can be combined with preload in widget. When `true` the audio and video inputs will be muted by default. (This means there currently is no way to start without muted video if one wants to skip the lobby. Also not in widget mode.)                                                                                                                      |
 | `theme`                                        | One of: `light`, `dark`, `light-high-contrast`, `dark-high-contrast`                                                                                               | No, defaults to `dark`                                                                            | No, defaults to `dark`       | UI theme to use.                                                                                                                                                                                                                                                                                                                                                                                    |
+| `background`                                   | One of: `solid`, `gradient`                                                                                                                                        | No, defaults to `gradient`                                                                        | No, defaults to `gradient`   | Visual style of the page background.                                                                                                                                                                                                                                                                                                                                                                |
 | `viaServers`                                   | Comma separated list of [Matrix Server Names](https://spec.matrix.org/v1.12/appendices/#server-name)                                                               | Not applicable                                                                                    | No                           | Homeserver for joining a room, non-empty value required for rooms not on the user’s default homeserver.                                                                                                                                                                                                                                                                                             |
 | `sendNotificationType`                         | `ring` or `notification`                                                                                                                                           | No                                                                                                | No                           | Will send a "ring" or "notification" `m.rtc.notification` event if the user is the first one in the call.                                                                                                                                                                                                                                                                                           |
-| `autoLeaveWhenOthersLeft`                      | `true` or `false`                                                                                                                                                  | No, defaults to `false`                                                                           | No, defaults to `false`      | Whether the app should automatically leave the call when there is no one left in the call.                                                                                                                                                                                                                                                                                                          |
+| `autoLeave`                                    | `true` or `false`                                                                                                                                                  | No, defaults to `false`                                                                           | No, defaults to `false`      | Whether the app should automatically leave the call when there is no one left in the call.                                                                                                                                                                                                                                                                                                          |
 | `waitForCallPickup`                            | `true` or `false`                                                                                                                                                  | No, defaults to `false`                                                                           | No, defaults to `false`      | When sending a notification, show UI that the app is awaiting an answer, play a dial tone, and (in widget mode) auto-close the widget once the notification expires.                                                                                                                                                                                                                                |
 
 ### Widget-only parameters

embedded/android/gradle/libs.versions.toml

@@ -9,4 +9,4 @@ android_gradle_plugin = { module = "com.android.tools.build:gradle", version.ref
 
 [plugins]
 android_library = { id = "com.android.library", version.ref = "android_gradle_plugin" }
-maven_publish = { id = "com.vanniktech.maven.publish", version = "0.36.0" }
+maven_publish = { id = "com.vanniktech.maven.publish", version = "0.36.0" }

eslint/CopyrightHeader.js

@@ -0,0 +1,66 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { ESLintUtils } from "@typescript-eslint/utils";
+
+const rule = ESLintUtils.RuleCreator(
+  () => "https://github.com/element-hq/element-call",
+)({
+  name: "copyright-header",
+  meta: {
+    type: "problem",
+    fixable: "code",
+    docs: {
+      description: "Require a copyright header in files.",
+    },
+    messages: {
+      noHeader: "Copyright header is required.",
+    },
+    schema: [{ type: "string" }],
+  },
+  create(context) {
+    const code = context.getSourceCode();
+
+    return {
+      Program(node) {
+        const firstToken = code.getFirstToken(node, { includeComments: false });
+
+        if (!firstToken) {
+          return;
+        }
+
+        const headComments = code.getCommentsBefore(firstToken);
+        const hasSomeCopyrightHeader = headComments?.some((comment) =>
+          comment?.value?.includes("Copyright"),
+        );
+        if (hasSomeCopyrightHeader) {
+          return;
+        }
+        const headerTemplate = context.options[0];
+        const fix = headerTemplate
+          ? function (fixer) {
+              return fixer.insertTextBefore(
+                firstToken,
+                headerTemplate.replace(
+                  /%%CURRENT_YEAR%%/g,
+                  new Date().getFullYear(),
+                ),
+              );
+            }
+          : undefined;
+
+        context.report({
+          messageId: "noHeader",
+          node,
+          fix,
+        });
+      },
+    };
+  },
+});
+
+export default rule;

eslint/NoObservableScopeLeak.js

@@ -0,0 +1,78 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { ESLintUtils } from "@typescript-eslint/utils";
+
+// These ObservableScope methods will not generally cause resource leaks even if
+// called from a callback
+const safeScopeMethods = new Set(["bind", "end"]);
+
+/**
+ * Determines whether the variable with the given name is local to
+ * the enclosing function or class scope.
+ */
+function isLocal(name, scope) {
+  // If it is nowhere to be found in the "through" scope, it is local.
+  if (!scope.through.some(({ identifier }) => identifier.name === name))
+    return true;
+  if (scope.type === "function" || scope.type === "class") return false;
+  // If this is something other than a function or class scope, check its outer
+  // scope.
+  return !scope.upper || isLocal(name, scope.upper);
+}
+
+const rule = ESLintUtils.RuleCreator(
+  () => "https://github.com/element-hq/element-call",
+)({
+  name: "no-observablescope-leak",
+  meta: {
+    type: "problem",
+    docs: {
+      description:
+        "Require referenced ObservableScopes to be defined in the very same scope to avoid resource leaks.",
+    },
+    messages: {
+      scopeLeak:
+        "Do not reference ObservableScopes defined in an outer scope; this may create resource leaks.",
+    },
+    schema: [],
+  },
+  create(context) {
+    return {
+      Identifier(node) {
+        const scope = context.sourceCode.getScope(node);
+        if (
+          // Is this a reference to a variable defined in an outer scope?
+          !isLocal(node.name, scope) &&
+          // Exclude calls to "safe" ObservableScope methods
+          node.parent?.type === "MemberExpression" &&
+          node.parent.object === node &&
+          node.parent.property.type === "Identifier" &&
+          !safeScopeMethods.has(node.parent.property.name) &&
+          /(^s|S)cope$/.test(node.name)
+        ) {
+          // TODO: Once oxlint supports lint rules that rely on TypeScript type-awareness,
+          // Verify that the variable is actually of type ObservableScope rather than just
+          // checking its name. This is expensive so we should do this last.
+          //
+          // const services = ESLintUtils.getParserServices(context);
+          // const type = services.getTypeAtLocation(node);
+          // if (type.symbol?.name === "ObservableScope") { ... }
+
+          // This ObservableScope method call may be causing resource leaks.
+          context.report({
+            messageId: "scopeLeak",
+            loc: node.loc,
+            node,
+          });
+        }
+      },
+    };
+  },
+});
+
+export default rule;

eslint/NoTopLevelLoggerGetChild.js

@@ -0,0 +1,92 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { ESLintUtils } from "@typescript-eslint/utils";
+
+/**
+ * Node types that introduce a new non-module scope. A getChild() call nested
+ * inside any of these is considered "not at the top level".
+ */
+const FUNCTION_OR_CLASS_TYPES = new Set([
+  "FunctionDeclaration",
+  "FunctionExpression",
+  "ArrowFunctionExpression",
+  "ClassBody",
+]);
+
+const rule = ESLintUtils.RuleCreator(
+  () => "https://github.com/element-hq/element-call",
+)({
+  name: "no-top-level-logger-get-child",
+  meta: {
+    type: "problem",
+    docs: {
+      description:
+        "Disallow calling logger.getChild() at the top level of a module." +
+        "`getChild` has to be called after the rageshake logger `init()`." +
+        "If it is called at the top level the child logger will never be setup for rageshakes.",
+    },
+    messages: {
+      noTopLevelGetChild:
+        "Do not call logger.getChild() at the top level of a module; move it inside a function or class instead that gets called after rageshake logger `init()` is called.",
+    },
+    schema: [],
+  },
+  create(context) {
+    // Tracks the local binding names that refer to the logger imported from
+    // 'matrix-js-sdk/lib/logger', e.g. both `logger` and `rootLogger` in:
+    //   import { logger } from "matrix-js-sdk/lib/logger";
+    //   import { logger as rootLogger } from "matrix-js-sdk/lib/logger";
+    const loggerNames = new Set();
+
+    return {
+      ImportDeclaration(node) {
+        if (node.source.value !== "matrix-js-sdk/lib/logger") return;
+        for (const specifier of node.specifiers) {
+          if (
+            specifier.type === "ImportSpecifier" &&
+            specifier.imported.name === "logger"
+          ) {
+            loggerNames.add(specifier.local.name);
+          }
+        }
+      },
+
+      CallExpression(node) {
+        // Must be a non-computed member expression call: something.getChild(...)
+        if (
+          node.callee.type !== "MemberExpression" ||
+          node.callee.computed ||
+          node.callee.property.type !== "Identifier" ||
+          node.callee.property.name !== "getChild"
+        )
+          return;
+
+        // The receiver must be one of the tracked logger names.
+        const object = node.callee.object;
+        if (object.type !== "Identifier" || !loggerNames.has(object.name))
+          return;
+
+        // Flag the call only when it is at module top level — i.e. there is no
+        // enclosing function or class body anywhere in the ancestor chain.
+        const ancestors = context.sourceCode.getAncestors(node);
+        const isTopLevel = !ancestors.some((a) =>
+          FUNCTION_OR_CLASS_TYPES.has(a.type),
+        );
+
+        if (isTopLevel) {
+          context.report({
+            messageId: "noTopLevelGetChild",
+            node,
+          });
+        }
+      },
+    };
+  },
+});
+
+export default rule;

eslint/SdkImportBoundary.js

@@ -0,0 +1,128 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { dirname, resolve, sep } from "node:path";
+import { ESLintUtils } from "@typescript-eslint/utils";
+
+/**
+ * Packages a host supplies and the SDK must not know about: UI, i18n and
+ * Element Call's design system.
+ */
+const BANNED_PACKAGES = [
+  "react",
+  "react-dom",
+  "react-i18next",
+  "i18next",
+  "@vector-im/",
+];
+
+/**
+ * Packages only a media backend may import. The session speaks MatrixRTC and
+ * sees media through `sdk/src/media-backend/api.ts`; a backend under
+ * `sdk/src/media-backend/<name>/` is the one place its protocol's library appears.
+ */
+const BACKEND_PACKAGES = ["livekit-client", "@livekit/"];
+
+/**
+ * Keeps the SDK free of Element Call: nothing under `sdk/` may import a file
+ * outside `sdk/` by relative path (that is `src/`, `component/`,
+ * `playwright/`) or one of the packages above. The development harness under
+ * `sdk/dev/` is a host, not part of the library, and is exempt. Keeps the
+ * session free of any one media backend, too: outside `sdk/src/media-backend/`,
+ * a backend's packages may only be imported for their types, and only in
+ * the public API, the errors and the test helpers that have to name them.
+ */
+const rule = ESLintUtils.RuleCreator(
+  () => "https://github.com/element-hq/element-call",
+)({
+  name: "sdk-import-boundary",
+  meta: {
+    type: "problem",
+    docs: {
+      description:
+        "Disallow the SDK importing Element Call (anything outside sdk/) or host-supplied packages.",
+    },
+    messages: {
+      outsideSdk:
+        "The SDK must not import '{{specifier}}': it resolves outside sdk/. Copy or move what it needs into sdk/src.",
+      bannedPackage:
+        "The SDK must not import '{{specifier}}': a host supplies that, the SDK has no UI.",
+      backendPackage:
+        "Only a media backend under sdk/src/media-backend/ may import '{{specifier}}'; the session sees media through media-backend/api.ts.",
+    },
+    schema: [],
+  },
+  defaultOptions: [],
+  create(context) {
+    const filename = context.filename;
+    const sdkRoot = resolve(context.cwd, "sdk") + sep;
+    if (!filename.startsWith(sdkRoot)) return {};
+    if (filename.startsWith(resolve(sdkRoot, "dev") + sep)) return {};
+    const inBackend = filename.startsWith(
+      resolve(sdkRoot, "src", "media-backend") + sep,
+    );
+
+    const matchesPackage = (specifier, pkg) =>
+      specifier === pkg ||
+      specifier.startsWith(pkg.endsWith("/") ? pkg : `${pkg}/`);
+
+    const check = (node, specifier, typeOnly = false) => {
+      if (typeof specifier !== "string") return;
+      if (
+        !inBackend &&
+        !typeOnly &&
+        BACKEND_PACKAGES.some((pkg) => matchesPackage(specifier, pkg))
+      ) {
+        context.report({
+          node,
+          messageId: "backendPackage",
+          data: { specifier },
+        });
+        return;
+      }
+      if (specifier.startsWith(".")) {
+        const target = resolve(dirname(filename), specifier);
+        if (!target.startsWith(sdkRoot))
+          context.report({
+            node,
+            messageId: "outsideSdk",
+            data: { specifier },
+          });
+      } else if (
+        BANNED_PACKAGES.some((pkg) => matchesPackage(specifier, pkg))
+      ) {
+        context.report({
+          node,
+          messageId: "bannedPackage",
+          data: { specifier },
+        });
+      }
+    };
+
+    return {
+      ImportDeclaration(node) {
+        check(
+          node,
+          node.source.value,
+          node.importKind === "type" ||
+            node.specifiers.every((s) => s.importKind === "type"),
+        );
+      },
+      ExportNamedDeclaration(node) {
+        if (node.source) check(node, node.source.value);
+      },
+      ExportAllDeclaration(node) {
+        check(node, node.source.value);
+      },
+      ImportExpression(node) {
+        if (node.source.type === "Literal") check(node, node.source.value);
+      },
+    };
+  },
+});
+
+export default rule;

eslint/index.js

@@ -0,0 +1,9 @@
+module.exports = {
+  rules: {
+    "copyright-header": require("./CopyrightHeader").default,
+    "no-observablescope-leak": require("./NoObservableScopeLeak").default,
+    "no-top-level-logger-get-child": require("./NoTopLevelLoggerGetChild")
+      .default,
+    "sdk-import-boundary": require("./SdkImportBoundary").default,
+  },
+};

eslint/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "eslint-plugin-element-call",
+  "version": "0.0.0"
+}

knip.ts

@@ -9,32 +9,45 @@ import { type KnipConfig } from "knip";
 
 export default {
   vite: {
-    config: ["vite.config.ts", "vite-embedded.config.ts", "vite-sdk.config.ts"],
+    config: [
+      "vite.config.ts",
+      "vite-embedded.config.ts",
+      "vite-sdk.config.ts",
+      "vite-sdk-dev.config.ts",
+      "vite-sdk-target-based-on-call-view-model.config.ts",
+      "vite-component.config.ts",
+      "vite-component-dev.config.ts",
+    ],
   },
-  entry: ["src/main.tsx", "i18next.config.ts"],
+  entry: ["src/main.tsx", "eslint/index.js", "i18next.config.ts"],
   ignoreBinaries: [
     // This is deprecated, so Knip doesn't actually recognize it as a globally
     // installed binary. TODO We should switch to Compose v2:
     // https://docs.docker.com/compose/migrate/
     "docker-compose",
+    // This is a shell built-in.
+    "printf",
+  ],
+  ignoreFiles: [
+    "scripts/.pnpmfile.cjs",
+    // Deliberately added prior to any component or business logic
+    // implementation
+    "src/state/ServiceInterruptionsViewModel.ts",
   ],
-  ignoreFiles: ["scripts/.pnpmfile.cjs"],
   ignoreDependencies: [
     // Used in CSS
     "normalize.css",
     // Used for its global type declarations
     "@types/grecaptcha",
-    // Because we use matrix-js-sdk as a Git dependency rather than consuming
-    // the proper release artifacts, and also import directly from src/, we're
-    // forced to re-install some of the types that it depends on even though
-    // these look unused to Knip
-    "@types/content-type",
     "@types/sdp-transform",
     // We obviously use this, but if the package has been linked with pnpm link,
     // then Knip will flag it as a false positive
     // https://github.com/webpro-nl/knip/issues/766
     "@vector-im/compound-web",
     "matrix-widget-api",
+    // Used by oxlint
+    "eslint-plugin-element-call",
+    "eslint-plugin-storybook",
   ],
   ignoreExportsUsedInFile: true,
 } satisfies KnipConfig;

locales/cs/app.json

@@ -102,11 +102,15 @@
     "connection_lost_description": "Hovor byl přerušen.",
     "e2ee_unsupported": "Nekompatibilní prohlížeč",
     "e2ee_unsupported_description": "Váš webový prohlížeč nepodporuje šifrované hovory. Mezi podporované prohlížeče patří Chrome, Safari a Firefox 117+.",
+    "failed_to_start_livekit": "Nepodařilo se navázat připojení k Livekitu",
     "generic": "Něco se pokazilo.",
     "generic_description": "Odeslání protokolů ladění nám pomůže vystopovat problém.",
     "insufficient_capacity": "Nedostatečná kapacita",
     "insufficient_capacity_description": "Server dosáhl své maximální kapacity a v tuto chvíli se nemůžete připojit k hovoru. Zkuste to později nebo se obraťte na správce serveru, pokud problém přetrvává.",
     "matrix_rtc_transport_missing": "Server není nakonfigurován pro práci s {{brand}}. Obraťte se na správce serveru (Doména: {{domain}}, Kód chyby: {{ errorCode }}).",
+    "membership_manager": "Chyba Správce členství",
+    "membership_manager_description": "Správce členství musel být ukončen. To je způsobeno mnoha po sobě jdoucími neúspěšnými síťovými požadavky.",
+    "no_matrix_2_authorization_service": "Autorizační služba vašeho mediálního serveru (SFU) je zastaralá.",
     "open_elsewhere": "Otevřeno na jiné kartě",
     "open_elsewhere_description": "{{brand}} byl otevřen v jiné záložce. Pokud to nezní správně, zkuste stránku znovu načíst.",
     "room_creation_restricted": "Nepodařilo se vytvořit hovor",
@@ -141,6 +145,7 @@
   },
   "layout_grid_label": "Mřížka",
   "layout_spotlight_label": "Soustředěný mód",
+  "layout_switch_label": "Rozvržení",
   "lobby": {
     "ask_to_join": "Žádost o připojení k hovoru",
     "join_as_guest": "Připojte se jako host",
@@ -241,11 +246,14 @@
   "version": "{{productName}}verze: {{version}}",
   "video_tile": {
     "always_show": "Vždy zobrazit",
+    "call_ended": "Hovor ukončen",
+    "calling": "Volání…",
     "camera_starting": "Načítání videa...",
     "collapse": "Sbalit",
     "expand": "Rozbalit",
     "mute_for_me": "Pro mě ztlumit",
     "muted_for_me": "Pro mě ztlumené",
+    "screen_share_volume": "Hlasitost sdílení obrazovky",
     "volume": "Hlasitost",
     "waiting_for_media": "Čekání na média..."
   }

locales/en/app.json

@@ -59,10 +59,10 @@
   "developer_mode": {
     "always_show_iphone_earpiece": "Show iPhone earpiece option on all platforms",
     "crypto_version": "Crypto version: {{version}}",
-    "custom_livekit_url": {
-      "current_url": "Currently set to: ",
-      "from_config": "Currently, no overwrite is set. Url from well-known or config is used.",
-      "label": "Custom Livekit-url",
+    "custom_transport": {
+      "current": "Currently set to: ",
+      "from_config": "Currently, no overwrite is set. Url from config is used.",
+      "label": "Custom transport JSON",
       "reset": "Reset overwrite",
       "save": "Save",
       "saving": "Saving..."
@@ -80,10 +80,6 @@
         "description": "Compatible with homeservers that do not support sticky events (but all other EC clients are v0.17.0 or later)",
         "label": "Compatibility: state events & multi SFU"
       },
-      "Legacy": {
-        "description": "Compatible with old versions of EC that do not support multi SFU",
-        "label": "Legacy: state events & oldest membership SFU"
-      },
       "Matrix_2_0": {
         "description": "Compatible only with homservers supporting sticky events and all EC clients v0.17.0 or later",
         "label": "Matrix 2.0: sticky events & multi SFU"
@@ -110,7 +106,7 @@
     "insufficient_capacity_description": "The server has reached its maximum capacity and you cannot join the call at this time. Try again later, or contact your server admin if the problem persists.",
     "livekit_connection_error": "Failed to connect to Livekit server",
     "livekit_connection_error_description": "An error occurred while connecting to the Livekit server (<1>Reason:</1> <2>{{ reason }}</2>).",
-    "matrix_rtc_transport_missing": "The server is not configured to work with {{brand}}. Please contact your server admin (Domain: {{domain}}, Error Code: {{ errorCode }}).",
+    "matrix_rtc_transport_missing": "The server is not configured to work with {{brand}} and no other call participant provides a usable transport. Please contact your server admin (Domain: {{domain}}, Error Code: {{ errorCode }}).",
     "membership_manager": "Membership Manager Error",
     "membership_manager_description": "The Membership Manager had to shut down. This is caused by many consecutive failed network requests.",
     "no_matrix_2_authorization_service": "The authorization service for your media server (SFU) is out of date.",
@@ -120,6 +116,7 @@
     "peer_connection_timeout_description": "Connection to the media server timed out. Try switching to a different network or disabling your VPN. If the problem persists, see our <0>troubleshooting guide</0> or contact your server administrator.",
     "room_creation_restricted": "Failed to create call",
     "room_creation_restricted_description": "Call creation might be restricted to authorized users only. Try again later, or contact your server admin if the problem persists.",
+    "screen_share_failed": "Could not start screen sharing",
     "sticky_events_required": "Homeserver does not support Matrix 2.0 calls",
     "sticky_events_required_description": "This deployment is configured to use Matrix 2.0 call mode, but the homeserver does not advertise support for sticky events (MSC4354). Ask your server admin to upgrade, or switch the deployment to a compatible mode.",
     "unexpected_ec_error": "An unexpected error occurred (<0>Error Code:</0> <1>{{ errorCode }}</1>). Please contact your server admin."
@@ -166,6 +163,12 @@
   "login_auth_links_prompt": "Not registered yet?",
   "login_subheading": "To continue to Element",
   "login_title": "Login",
+  "microphone_level": {
+    "label": "Microphone level",
+    "no_device": "No microphone found. Connect one, then try again.",
+    "permission_denied": "Microphone access is blocked. Allow it, then try again.",
+    "value": "{{level}} of {{max}}"
+  },
   "microphone_off": "Microphone off",
   "microphone_on": "Microphone on",
   "mute_microphone_button_label": "Mute microphone",
@@ -196,33 +199,50 @@
   "room_auth_view_ssla_caption": "By clicking \"Join call now\", you agree to our <2>Software and Services License Agreement (SSLA)</2>",
   "screenshare_button_label": "Share screen",
   "settings": {
+    "advanced_camera_description": "Configure resolution, framerate, bitrate, and codec for camera video. Changes apply on next call join.",
+    "advanced_camera_label": "Advanced camera settings",
+    "advanced_screen_share_description": "Configure resolution, framerate, bitrate, and codec for screen sharing",
+    "advanced_screen_share_label": "Advanced screen share settings",
+    "audio_processing_description": "Changes apply on next call join.",
+    "audio_processing_header": "Audio processing",
     "audio_tab": {
       "effect_volume_description": "Adjust the volume at which reactions and hand raised effects play.",
       "effect_volume_label": "Sound effect volume"
     },
+    "auto_gain_control_label": "Automatic gain control",
     "background_blur_header": "Background",
     "background_blur_label": "Blur the background of the video",
+    "bitrate_label": "Bitrate",
     "blur_not_supported_by_browser": "(Background blur is not supported by this device.)",
+    "camera_header": "Camera quality",
+    "codec_label": "Codec",
     "developer_tab_title": "Developer",
     "devices": {
+      "activating": "Activating…",
       "camera": "Camera",
       "camera_numbered": "Camera {{n}}",
+      "camera_source": "Camera Source",
       "change_device_button": "Change audio device",
       "default": "Default",
       "default_named": "Default <2>({{name}})</2>",
+      "default_named_plain": "Default ({{name}})",
       "handset": "Handset",
       "loudspeaker": "Loudspeaker",
+      "mic_source": "Mic Source",
       "microphone": "Microphone",
       "microphone_numbered": "Microphone {{n}}",
       "speaker": "Speaker",
       "speaker_numbered": "Speaker {{n}}"
     },
+    "echo_cancellation_label": "Echo cancellation",
     "feedback_tab_body": "If you are experiencing issues or simply would like to provide some feedback, please send us a short description below.",
     "feedback_tab_description_label": "Your feedback",
     "feedback_tab_h4": "Submit feedback",
     "feedback_tab_send_logs_label": "Include debug logs",
     "feedback_tab_thank_you": "Thanks, we received your feedback!",
     "feedback_tab_title": "Feedback",
+    "framerate_label": "Framerate",
+    "noise_suppression_label": "Noise suppression",
     "opt_in_description": "<0></0><1></1>You may withdraw consent by unchecking this box. If you are currently in a call, this setting will take effect at the end of the call.",
     "preferences_tab": {
       "developer_mode_label": "Developer mode",
@@ -234,7 +254,9 @@
       "reactions_show_label": "Show reactions",
       "show_hand_raised_timer_description": "Show a timer when a participant raises their hand",
       "show_hand_raised_timer_label": "Show hand raise duration"
-    }
+    },
+    "resolution_label": "Resolution",
+    "screen_share_header": "Screen sharing"
   },
   "star_rating_input_label_one": "{{count}} star",
   "star_rating_input_label_other": "{{count}} stars",

locales/et/app.json

@@ -3,6 +3,7 @@
     "user_menu": "Kasutajamenüü"
   },
   "action": {
+    "blur_background": "Hägusta tausta",
     "close": "Sulge",
     "copy_link": "Kopeeri link",
     "edit": "Muuda",
@@ -72,8 +73,20 @@
     "environment_variables": "Keskkonnamuutujad",
     "hostname": "Hosti nimi: {{hostname}}",
     "livekit_server_info": "LiveKiti serveri teave",
-    "livekit_sfu": "LiveKit SFU: {{url}}",
+    "livekit_sfu": "LiveKiti meediaedastusserver (SFU): {{url}}",
     "matrixRTCMode": {
+      "Comptibility": {
+        "description": "Ühildub koduserveritega, mis ei toeta määratud kestusega sündmuseid (kuid kõik teised EC kliendid on v0.17.0 või hilisemad)",
+        "label": "Ühilduvus: olekusündmused ja mitu meediaedastusserverit (SFU)"
+      },
+      "Legacy": {
+        "description": "Ühildub EC vanemate versioonidega, millel puudub mitme meediaedastusserveri (SFU) tugi",
+        "label": "Vana lahendus: oleku üritused ja vanim meediaedastusserver (SFU)"
+      },
+      "Matrix_2_0": {
+        "description": "Ühildub ainult määratud kestusega sündmuseid toetavate koduserveritega ja kõigi EC-klientidega alates versioonist 0.17.0",
+        "label": "Matrix 2.0: määratud kestusega sündmused ja mitu meediaedastusserverit (SFU)"
+      },
       "title": "MatrixRTC režiim"
     },
     "matrix_id": "Matrixi kasutajatunnus: {{id}}",
@@ -95,13 +108,20 @@
     "generic_description": "Silumis- ja vealogide saatmine võib aidata meid vea põhjuseni jõuda.",
     "insufficient_capacity": "Mittepiisav jõudlus",
     "insufficient_capacity_description": "Serveri jõudluse ülempiir on hetkel ületatud ja sa ei saa hetkel selle kõnega liituda. Proovi hiljem uuesti või kui probleem kestab kauem, siis võta ühendust serveri haldajaga.",
+    "livekit_connection_error": "Livekiti serveriga ühendamine ei õnnestunud",
+    "livekit_connection_error_description": "Livekiti serveriga ühendamisel tekkis viga (<1>Põhjus: </1> <2>{{ reason }}</2>).",
     "matrix_rtc_transport_missing": "See server pole seadistatud töötama rakendusega {{brand}}. Palun võta ühendust serveri halduriga (domeen: {{domain}}, veakood: {{ errorCode }}).",
     "membership_manager": "Viga liikmelisuse haldamisel",
     "membership_manager_description": "Liikmelisuse haldur pidi oma töö lõpetama. Selle põhjuseks olid paljud järjestikused ebaõnnestunud võrgupäringud.",
+    "no_matrix_2_authorization_service": "Sinu meediaedastusserveri (SFU) autoriseerimisteenus on aegunud.",
     "open_elsewhere": "Avatud teisel vahekaardil",
     "open_elsewhere_description": "{{brand}} on avatud teisel vahekaardil. Kui see ei tundu olema õige, proovi selle lehe uuesti laadimist.",
+    "peer_connection_timeout": "Ühendus aegus",
+    "peer_connection_timeout_description": "Meediaserveriga ühenduspäring aegus. Proovi kasutada muud võrku või keelata VPN-i kasutamine. Kui probleem püsib, vaata meie <0> veaotsingu juhendit</0> või võta ühendust oma serveri peakasutajaga.",
     "room_creation_restricted": "Kõne loomine ei õnnestunud",
     "room_creation_restricted_description": "Kõne loomine võib olla lubatud ainult volitatud kasutajatele. Proovi hiljem uuesti või probleemi püsimisel võta ühendust oma serveri haldajaga.",
+    "sticky_events_required": "Koduserver ei toeta Matrix 2.0 kõnesid",
+    "sticky_events_required_description": "See server on seadistatud kasutama Matrix 2.0 kõnerežiimi, kuid koduserver ei teata, et tal selleks vajalike sündmuste (MSC4354) tugi. Palu serveri peakasutajal see uuendada või kasuta koduserveris ühilduvat režiimi.",
     "unexpected_ec_error": "Tekkis ootamatu viga (<0>Veakood:</0> <1>{{ errorCode }}</1>). Palun võta ühendust serveri haldajaga."
   },
   "group_call_loader": {
@@ -132,6 +152,7 @@
   },
   "layout_grid_label": "Ruudustik",
   "layout_spotlight_label": "Rambivalgus",
+  "layout_switch_label": "Paigutus",
   "lobby": {
     "ask_to_join": "Küsi võimalust liituda kõnega",
     "join_as_guest": "Liitu külalisena",
@@ -184,6 +205,7 @@
     "blur_not_supported_by_browser": "(Tausta hägustamine pole selles seadmes toetatud.)",
     "developer_tab_title": "Arendaja",
     "devices": {
+      "activating": "Aktiveerin…",
       "camera": "Kaamera",
       "camera_numbered": "Kaamera {{n}}",
       "change_device_button": "Muuda heliseadet",
@@ -223,6 +245,7 @@
   "stop_video_button_label": "Peata videovoog",
   "submitting": "Saadan…",
   "switch_camera": "Vaheta kaamerat",
+  "technical_details": "Tehnilised üksikasjad",
   "unauthenticated_view_body": "Sa pole veel registreerunud? <2>Loo kasutajakonto</2>",
   "unauthenticated_view_login_button": "Logi oma kontosse sisse",
   "unauthenticated_view_ssla_caption": "Klõpsides „Jätka“ nõustud sa meie <2>Tarkvara ja teenuste litsentseerimise lepinguga (Software and Services License Agreement - SSLA)</2>",
@@ -230,11 +253,14 @@
   "version": "{{productName}}, versioon: {{version}}",
   "video_tile": {
     "always_show": "Näita alati",
+    "call_ended": "Kõne lõppes",
+    "calling": "Helistan…",
     "camera_starting": "Video on laadimisel...",
     "collapse": "Näita vähem",
     "expand": "Näita rohkem",
     "mute_for_me": "Summuta minu jaoks",
     "muted_for_me": "Minule summutatud",
+    "screen_share_volume": "Helivaljus ekraanijagaamisel",
     "volume": "Helivaljus",
     "waiting_for_media": "Ootame kuni meedia on olemas..."
   }

locales/fi/app.json

@@ -3,6 +3,7 @@
     "user_menu": "Käyttäjävalikko"
   },
   "action": {
+    "blur_background": "Sumenna tausta",
     "close": "Sulje",
     "copy_link": "Kopioi linkki",
     "edit": "Muokkaa",
@@ -107,14 +108,20 @@
     "generic_description": "Vianmäärityslokien lähettäminen auttaa meitä jäljittämään ongelman.",
     "insufficient_capacity": "Riittämätön kapasiteetti",
     "insufficient_capacity_description": "Palvelin on saavuttanut maksimikapasiteettinsa, etkä voi liittyä puheluun tällä hetkellä. Yritä myöhemmin uudelleen tai ota yhteyttä palvelimen ylläpitäjään, jos ongelma jatkuu.",
+    "livekit_connection_error": "Yhteyden muodostaminen Livekit-palvelimeen epäonnistui",
+    "livekit_connection_error_description": "Livekit-palvelimeen yhteyden muodostamisessa tapahtui virhe (<1>Syy: </1> <2>{{ reason }}</2>).",
     "matrix_rtc_transport_missing": "Palvelinta ei ole määritetty toimimaan {{brand}} -sovelluksen kanssa. Ota yhteyttä palvelimen ylläpitäjään (Verkkotunnus: {{domain}}, Virhekoodi: {{ errorCode }}).",
     "membership_manager": "Jäsenyydenhallinnan virhe",
     "membership_manager_description": "Jäsenyyshallinta jouduttiin sulkemaan. Tämä johtui useista peräkkäisistä epäonnistuneista verkkopyynnöistä.",
     "no_matrix_2_authorization_service": "Mediapalvelimesi (SFU) valtuutuspalvelu on vanhentunut.",
     "open_elsewhere": "Avattu toisessa välilehdessä",
     "open_elsewhere_description": "{{brand}} on avattu toisessa välilehdessä. Jos tämä ei kuulosta oikealta, yritä ladata sivu uudelleen.",
+    "peer_connection_timeout": "Yhteyden aikakatkaisu",
+    "peer_connection_timeout_description": "Yhteys mediapalvelimeen aikakatkaistiin. Kokeile vaihtaa verkkoa tai poistaa VPN käytöstä. Jos ongelma jatkuu, katso <0>vianetsintäoppaamme</0> tai ota yhteyttä palvelimesi ylläpitäjään.",
     "room_creation_restricted": "Puhelun luominen epäonnistui",
     "room_creation_restricted_description": "Puheluiden luominen saattaa olla rajoitettu vain valtuutetuille käyttäjille. Yritä myöhemmin uudelleen tai ota yhteyttä palvelimen ylläpitäjään, jos ongelma jatkuu.",
+    "sticky_events_required": "Kotipalvelin ei tue Matrix 2.0 -puheluita",
+    "sticky_events_required_description": "Tämä asennus on määritetty käyttämään Matrix 2.0 -puhelutilaa, mutta kotipalvelin ei mainosta tukea tarttuville tapahtumille (MSC4354). Pyydä palvelimen järjestelmänvalvojaa päivittämään tai vaihtamaan asennus yhteensopivaan tilaan.",
     "unexpected_ec_error": "Tapahtui odottamaton virhe (<0>Virhekoodi:</0> <1>{{ errorCode }}</1>). Ota yhteyttä palvelimen ylläpitäjään."
   },
   "group_call_loader": {
@@ -145,6 +152,7 @@
   },
   "layout_grid_label": "Ruudukko",
   "layout_spotlight_label": "Valokeila",
+  "layout_switch_label": "Asettelu",
   "lobby": {
     "ask_to_join": "Pyydä liittymistä puheluun",
     "join_as_guest": "Liity vieraana",
@@ -197,6 +205,7 @@
     "blur_not_supported_by_browser": "(Tämä laite ei tue taustan sumennusta.)",
     "developer_tab_title": "Kehittäjä",
     "devices": {
+      "activating": "Aktivoidaan…",
       "camera": "Kamera",
       "camera_numbered": "Kamera {{n}}",
       "change_device_button": "Vaihda äänilaite",
@@ -236,6 +245,7 @@
   "stop_video_button_label": "Lopeta video",
   "submitting": "Lähetetään…",
   "switch_camera": "Vaihda kameraa",
+  "technical_details": "Tekniset tiedot",
   "unauthenticated_view_body": "Etkö ole vielä rekisteröitynyt? <2>Luo tili</2>",
   "unauthenticated_view_login_button": "Kirjaudu tilillesi",
   "unauthenticated_view_ssla_caption": "Klikkaamalla \"Siirry\" hyväksyt <2>ohjelmisto- ja palvelulisenssisopimuksen (SSLA)</2>",

locales/pl/app.json

@@ -3,6 +3,7 @@
     "user_menu": "Menu użytkownika"
   },
   "action": {
+    "blur_background": "Rozmycie tła",
     "close": "Zamknij",
     "copy_link": "Kopiuj link",
     "edit": "Edytuj",
@@ -21,7 +22,7 @@
     "submit": "Wyślij",
     "upload_file": "Prześlij plik"
   },
-  "analytics_notice": "Uczestnicząc w tej becie, upoważniasz nas do zbierania anonimowych danych, które wykorzystamy do ulepszenia produktu. Dowiedz się więcej na temat danych, które zbieramy w naszej <2>Polityce prywatności</2> i <5>Polityce ciasteczek</5>.",
+  "analytics_notice": "Biorąc udział w wersji beta, wyrażasz zgodę na gromadzenie anonimowych danych, które wykorzystujemy w celu ulepszenia naszego produktu. Więcej informacji na temat danych, które śledzimy, znajdziesz w naszej <2>Polityce prywatności</2> dla i <6>Polityce ciasteczek</6>.",
   "call_ended_view": {
     "create_account_button": "Utwórz konto",
     "create_account_prompt": "<0>Może zechcesz ustawić hasło, aby zachować swoje konto?</0><1>Będziesz w stanie utrzymać swoją nazwę i ustawić awatar do wyświetlania podczas połączeń w przyszłości</1>",
@@ -41,7 +42,7 @@
     "display_name": "Nazwa wyświetlana",
     "encrypted": "Szyfrowane",
     "home": "Strona domowa",
-    "loading": "Ładowanie…",
+    "loading": "Wczytywanie…",
     "next": "Dalej",
     "options": "Opcje",
     "password": "Hasło",
@@ -58,6 +59,14 @@
   "developer_mode": {
     "always_show_iphone_earpiece": "Pokaż opcję słuchawki iPhone na wszystkich platformach",
     "crypto_version": "Wersja krypto: {{version}}",
+    "custom_livekit_url": {
+      "current_url": "Aktualnie ustawione na: ",
+      "from_config": "Aktualnie nie nadpisano ustawienia. Używany jest adres URL z dobrego źródła lub konfiguracji.",
+      "label": "Własny Livekit-url",
+      "reset": "Zresetuj nadpisanie",
+      "save": "Zapisz",
+      "saving": "Zapisuję..."
+    },
     "debug_tile_layout_label": "Układ kafelków Debug",
     "device_id": "ID urządzenia: {{id}}",
     "duplicate_tiles_label": "Liczba dodatkowych kopii kafelków na uczestnika",
@@ -65,6 +74,21 @@
     "hostname": "Nazwa hosta: {{hostname}}",
     "livekit_server_info": "Informacje serwera LiveKit",
     "livekit_sfu": "LiveKit SFU: {{url}}",
+    "matrixRTCMode": {
+      "Comptibility": {
+        "description": "Kompatybilny z serwerami domowymi, które nie obsługują sticky events (ale wszyscy inni klienci EC mają wersję v0.17.0 lub nowszą)",
+        "label": "Kompatybilność: state events & multi SFU"
+      },
+      "Legacy": {
+        "description": "Kompatybilny ze starszymi wersjami EC, które nie wspierają multi SFU",
+        "label": "Przestarzałe: state events & oldest membership SFU"
+      },
+      "Matrix_2_0": {
+        "description": "Kompatybilny tylko z serwerami domowymi obsługującymi sticky events i wszystkimi klientami EC w wersji v0.17.0 lub nowszej",
+        "label": "Matrix 2.0: sticky events & multi SFU"
+      },
+      "title": "Tryb MatrixRTC"
+    },
     "matrix_id": "ID Matrix: {{id}}",
     "mute_all_audio": "Wycisz cały dźwięk (uczestnicy, reakcje, dźwięki dołączenia)",
     "show_connection_stats": "Pokaż statystyki połączenia",
@@ -74,25 +98,36 @@
   "error": {
     "call_is_not_supported": "Połączenie nie jest obsługiwane",
     "call_not_found": "Nie znaleziono połączenia",
-    "call_not_found_description": "<0>Wygląda na to, że ten link nie należy do żadnego istniejącego połączenia. Sprawdź, czy posiadasz prawidłowy link lub <1>utwórz nowy</1>.</0>",
+    "call_not_found_description": "<0>Wygląda na to, że ten link nie należy do żadnego istniejącego połączenia. Sprawdź, czy masz prawidłowy link lub <2> utwórz nowy</2>.</0>",
     "connection_lost": "Utracono połączenie",
     "connection_lost_description": "Zostałeś rozłączony z rozmowy.",
     "e2ee_unsupported": "Niekompatybilna przeglądarka",
     "e2ee_unsupported_description": "Twoja przeglądarka nie wspiera szyfrowanych połączeń. Obsługiwane przeglądarki obejmują Chrome, Safari i Firefox 117+.",
+    "failed_to_start_livekit": "Nie udało się uruchomić połączenia Livekit",
     "generic": "Coś poszło nie tak",
     "generic_description": "Wysłanie dziennika debug, pozwoli nam namierzyć problem.",
     "insufficient_capacity": "Za mało miejsca",
     "insufficient_capacity_description": "Serwer osiągnął maksymalną pojemność, przez co nie możesz dołączyć do połączenia. Spróbuj ponownie później lub skontaktuj się z administratorem serwera, jeśli problem nie zniknie.",
+    "livekit_connection_error": "Nie udało się połączyć z serwerem Livekit",
+    "livekit_connection_error_description": "Wystąpił błąd podczas łączenia się z serwerem Livekit (<1>Przyczyna:</1> <2>{{ reason }}</2>).",
+    "matrix_rtc_transport_missing": "Serwer nie jest skonfigurowany do pracy z {{brand}}. Prosimy o kontakt z administratorem serwera (Domena: {{domain}}, Kod błędu: {{ errorCode }}).",
+    "membership_manager": "Błąd menedżera członkostwa",
+    "membership_manager_description": "Menedżer członkostwa został zamknięty przez zbyt wiele powtarzających się błędów połączenia.",
+    "no_matrix_2_authorization_service": "Usługa autoryzacji dla serwera multimediów (SFU) jest nieaktualna.",
     "open_elsewhere": "Otwarto w innej karcie",
     "open_elsewhere_description": "{{brand}} został otwarty w innej karcie. Jeśli tak nie jest, spróbuj odświeżyć stronę.",
+    "peer_connection_timeout": "Upłynął limit czasu połączenia",
+    "peer_connection_timeout_description": "Upłynął czas oczekiwania na połączenie z serwerem multimediów. Spróbuj połączyć się z inną siecią lub wyłączyć VPN. Jeśli problem nadal występuje, zapoznaj się z naszym <0>poradnikiem rozwiązywania problemów</0> lub skontaktuj się z administratorem serwera.",
     "room_creation_restricted": "Nie udało się utworzyć połączenia",
     "room_creation_restricted_description": "Tworzenie połączeń mogło zostać ograniczone tylko do autoryzowanych użytkowników. Spróbuj ponownie później lub skontaktuj się z administratorem serwera, jeśli problem nie minie.",
+    "sticky_events_required": "Serwer domowy nie wspiera połączeń Matrix 2.0",
+    "sticky_events_required_description": "Wybrana konfiguracja została ustawiona na korzystanie z połączeń Matrix 2.0, lecz serwer domowy nie wspiera ogłaszania sticky events (MSC4354). Poproś administratora serwera o aktualizację lub zmień konfigurację.",
     "unexpected_ec_error": "Wystąpił nieoczekiwany błąd (<0>Kod błędu:</0> <1>{{ errorCode }}</1>). Skontaktuj się z administratorem serwera."
   },
   "group_call_loader": {
     "banned_body": "Zostałeś zbanowany z pokoju.",
     "banned_heading": "Zbanowany",
-    "call_ended_body": "Zostałeś usunięty z rozmowy.",
+    "call_ended_body": "Zostałeś usunięty z połączenia.",
     "call_ended_heading": "Połączenie zakończone",
     "knock_reject_body": "Członkowie pokoju odrzucili Twoją prośbę o dołączenie.",
     "knock_reject_heading": "Nie możesz dołączyć",
@@ -112,17 +147,18 @@
   },
   "join_existing_call_modal": {
     "join_button": "Tak, dołącz do połączenia",
-    "text": "Te połączenie już istnieje, czy chcesz do niego dołączyć?",
+    "text": "Połączenie już istnieje, czy chcesz do niej dołączyć?",
     "title": "Dołączyć do istniejącego połączenia?"
   },
   "layout_grid_label": "Siatka",
   "layout_spotlight_label": "Centrum uwagi",
+  "layout_switch_label": "Układ",
   "lobby": {
-    "ask_to_join": "Poproś o dołączenie do rozmowy",
+    "ask_to_join": "Poproś o dołączenie do połączenia",
     "join_as_guest": "Dołącz jako gość",
     "join_button": "Dołącz do połączenia",
     "leave_button": "Wróć do ostatnie",
-    "waiting_for_invite": "Żądanie wysłane"
+    "waiting_for_invite": "Prośba wysłana! Oczekiwanie na zatwierdzenie…"
   },
   "log_in": "Zaloguj",
   "logging_in": "Logowanie…",
@@ -162,14 +198,15 @@
   "screenshare_button_label": "Udostępnij ekran",
   "settings": {
     "audio_tab": {
-      "effect_volume_description": "Dostosuj głośność, z jaką odtwarzane są efekty reakcji i podniesionej ręki",
-      "effect_volume_label": "Głośność efektu dźwiękowego"
+      "effect_volume_description": "Dostosuj głośność efektów reakcji i podniesienia ręki.",
+      "effect_volume_label": "Głośność efektów dźwiękowych"
     },
     "background_blur_header": "Tło",
     "background_blur_label": "Rozmycie tła wideo",
     "blur_not_supported_by_browser": "(Rozmycie tła nie jest wspierane przez to urządzenie.)",
     "developer_tab_title": "Programista",
     "devices": {
+      "activating": "Aktywuję…",
       "camera": "Kamera",
       "camera_numbered": "Kamera {{n}}",
       "change_device_button": "Zmień urządzenie audio",
@@ -192,7 +229,7 @@
     "preferences_tab": {
       "developer_mode_label": "Tryb programisty",
       "developer_mode_label_description": "Włącz tryb programisty i wyświetl kartę ustawień programisty.",
-      "introduction": "Tutaj możesz skonfigurować dodatkowe opcje dla lepszych doświadczeń.",
+      "introduction": "Tutaj możesz skonfigurować dodatkowe opcje dla lepszego komfortu użytkowania.",
       "reactions_play_sound_description": "Odtwórz efekt dźwiękowy, gdy ktoś wyślę reakcję w trakcie połączenia.",
       "reactions_play_sound_label": "Odtwórz dźwięki reakcji",
       "reactions_show_description": "Odtwórz animację, gdy ktoś wyślę reakcję.",
@@ -201,26 +238,31 @@
       "show_hand_raised_timer_label": "Pokaż czas po podniesieniu ręki"
     }
   },
-  "star_rating_input_label_one": "{{count}} gwiazdki",
-  "star_rating_input_label_other": "{{count}} gwiazdki",
+  "star_rating_input_label_one": "{{count}} gwiazdka",
+  "star_rating_input_label_few": "{{count}} gwiazdki",
+  "star_rating_input_label_many": "{{count}} gwiazdek",
   "start_new_call": "Rozpocznij nowe połączenie",
   "start_video_button_label": "Rozpocznij wideo",
   "stop_screenshare_button_label": "Udostępnianie ekranu",
   "stop_video_button_label": "Zakończ wideo",
   "submitting": "Wysyłanie…",
   "switch_camera": "Przełącz kamerę",
+  "technical_details": "Szczegóły techniczne",
   "unauthenticated_view_body": "Nie masz konta? <2>Utwórz je</2>",
-  "unauthenticated_view_login_button": "Zaloguj się do swojego konta",
+  "unauthenticated_view_login_button": "Zaloguj się na swoje konto",
   "unauthenticated_view_ssla_caption": "Klikając \"Przejdź\", wyrażasz zgodę na naszą <2>Umowę licencyjną oprogramowania i usług (SSLA)</2>",
-  "unmute_microphone_button_label": "Odcisz mikrofon",
-  "version": "Wersja: {{version}}",
+  "unmute_microphone_button_label": "Wyłącz wyciszenie mikrofonu",
+  "version": "{{productName}} wersja: {{version}}",
   "video_tile": {
     "always_show": "Zawsze pokazuj",
+    "call_ended": "Połączenie zakończone",
+    "calling": "Łączenie...",
     "camera_starting": "Wczytywanie wideo...",
     "collapse": "Zwiń",
     "expand": "Rozwiń",
     "mute_for_me": "Wycisz dla mnie",
     "muted_for_me": "Wyciszone dla mnie",
+    "screen_share_volume": "Głośność udostępniania ekranu",
     "volume": "Głośność",
     "waiting_for_media": "Oczekiwanie na media..."
   }

package.json

@@ -6,23 +6,34 @@
     "dev": "pnpm dev:full",
     "dev:full": "vite",
     "dev:embedded": "vite --config vite-embedded.config.js",
+    "dev:component": "vite --config vite-component-dev.config.ts",
+    "dev:sdk": "vite --config vite-sdk-dev.config.ts",
     "build": "pnpm build:full",
-    "build:full": "NODE_OPTIONS=--max-old-space-size=16384 vite build",
+    "build:full": "node --max-old-space-size=16384 node_modules/vite/bin/vite.js build",
     "build:full:production": "pnpm build:full",
     "build:full:development": "pnpm build:full --mode development",
     "build:embedded": "pnpm build:full --config vite-embedded.config.js",
     "build:embedded:production": "pnpm build:embedded",
     "build:embedded:development": "pnpm build:embedded --mode development",
-    "build:sdk:development": "pnpm build:sdk --mode development",
-    "build:sdk": "pnpm build:full --config vite-sdk.config.js",
-    "build:sdk:production": "pnpm build:sdk",
+    "build:sdk": "pnpm build:sdk:js && pnpm build:sdk:types",
+    "build:sdk:js": "pnpm build:full --config vite-sdk.config.js",
+    "build:sdk:types": "tsc -p sdk/tsconfig.build.json",
+    "build:sdk-target-based-on-call-view-model": "pnpm build:full --config vite-sdk-target-based-on-call-view-model.config.js",
+    "build:sdk:production": "pnpm build:sdk-target-based-on-call-view-model",
+    "build:sdk:development": "pnpm build:sdk-target-based-on-call-view-model --mode development",
+    "build:component": "pnpm build:component:js && pnpm build:component:types",
+    "build:component:js": "pnpm build:full --config vite-component.config.js",
+    "build:component:types": "tsc -p component/tsconfig.build.json",
+    "build:component:production": "pnpm build:component",
+    "build:component:development": "pnpm build:component:js --mode development && pnpm build:component:types",
     "serve": "vite preview",
-    "prettier:check": "prettier -c .",
-    "prettier:format": "prettier -w .",
-    "lint": "pnpm lint:types && pnpm lint:eslint && pnpm lint:knip",
-    "lint:eslint": "eslint --max-warnings 0 src playwright",
-    "lint:eslint-fix": "eslint --max-warnings 0 src playwright --fix",
+    "format": "oxfmt",
+    "format:check": "oxfmt --check; rc=$?; [[ $rc -ne 0 ]] && printf '\\033[46;30m INFO \\033[0m To fix, run: pnpm format\\n' >&2; exit $rc",
+    "lint": "pnpm lint:types && pnpm lint:oxlint && pnpm lint:knip && pnpm lint:externals",
+    "lint:oxlint": "oxlint src component sdk playwright",
+    "lint:oxlint-fix": "oxlint --fix src component sdk playwright",
     "lint:knip": "knip",
+    "lint:externals": "node scripts/check-component-externals.mjs",
     "lint:types": "tsc",
     "i18n": "npx i18next-cli extract",
     "i18n:check": "npx i18next-cli extract --ci",
@@ -30,8 +41,8 @@
     "test:storybook": "vitest --project=storybook",
     "test:unit": "vitest --project=unit",
     "test:coverage": "vitest --coverage",
-    "backend": "docker-compose -f dev-backend-docker-compose.yml up",
-    "backend-playwright": "docker-compose -f playwright-backend-docker-compose.yml -f playwright-backend-docker-compose.override.yml up",
+    "backend": "docker-compose -f docker-compose-dev.yml up",
+    "backend-playwright": "docker-compose -f docker-compose-dev.yml -f docker-compose-playwright.yml up",
     "test:playwright": "playwright test",
     "test:playwright:open": "pnpm test:playwright --ui",
     "links:on": "cp scripts/.pnpmfile.cjs .pnpmfile.cjs & pnpm install",
@@ -40,10 +51,6 @@
     "build-storybook": "storybook build"
   },
   "devDependencies": {
-    "@babel/core": "^7.16.5",
-    "@babel/preset-env": "^7.29.5",
-    "@babel/preset-react": "^7.22.15",
-    "@babel/preset-typescript": "^7.23.0",
     "@codecov/vite-plugin": "^1.3.0",
     "@fontsource/inconsolata": "^5.1.0",
     "@fontsource/inter": "^5.1.0",
@@ -51,7 +58,6 @@
     "@formatjs/intl-segmenter": "^11.7.3",
     "@livekit/components-core": "^0.12.0",
     "@livekit/components-react": "^2.0.0",
-    "@livekit/protocol": "^1.42.2",
     "@livekit/track-processors": "^0.7.1",
     "@mediapipe/tasks-vision": "^0.10.18",
     "@playwright/test": "^1.60.0",
@@ -59,17 +65,17 @@
     "@radix-ui/react-slider": "^1.1.2",
     "@radix-ui/react-visually-hidden": "^1.0.3",
     "@react-spring/web": "^10.0.0",
+    "@rolldown/plugin-babel": "^0.2.3",
     "@sentry/react": "^8.0.0",
     "@sentry/vite-plugin": "^3.0.0",
     "@storybook/addon-docs": "^10.3.6",
     "@storybook/addon-vitest": "^10.3.6",
     "@storybook/react-vite": "^10.3.6",
-    "@stylistic/eslint-plugin": "^3.0.0",
     "@testing-library/dom": "^10.1.0",
     "@testing-library/jest-dom": "^6.6.3",
     "@testing-library/react": "^16.0.0",
     "@testing-library/user-event": "^14.5.1",
-    "@types/content-type": "^1.1.5",
+    "@types/eslint": "^9.6.1",
     "@types/grecaptcha": "^3.0.9",
     "@types/jsdom": "^21.1.7",
     "@types/lodash-es": "^4.17.12",
@@ -79,34 +85,21 @@
     "@types/react": "^19.0.0",
     "@types/react-dom": "^19.0.0",
     "@types/sdp-transform": "^2.4.5",
-    "@typescript-eslint/eslint-plugin": "^8.31.0",
-    "@typescript-eslint/parser": "^8.31.0",
+    "@typescript-eslint/utils": "^8.61.0",
     "@use-gesture/react": "^10.2.11",
-    "@vector-im/compound-design-tokens": "^10.0.0",
-    "@vector-im/compound-web": "^9.3.0",
-    "@vitejs/plugin-react": "^4.0.1",
+    "@vector-im/compound-design-tokens": "^11.0.0",
+    "@vector-im/compound-web": "^10.4.0",
+    "@vitejs/plugin-react": "^6.0.2",
     "@vitest/browser-playwright": "^4.1.5",
     "@vitest/coverage-v8": "^4.0.18",
-    "@vitest/ui": "4.1.7",
-    "babel-plugin-transform-vite-meta-env": "^1.0.3",
+    "@vitest/ui": "4.1.11",
+    "babel-plugin-react-compiler": "^1.0.0",
     "classnames": "^2.3.1",
     "copy-to-clipboard": "^3.3.3",
-    "eslint": "^8.14.0",
-    "eslint-config-google": "^0.14.0",
-    "eslint-config-prettier": "^10.0.0",
-    "eslint-plugin-deprecate": "^0.9.0",
-    "eslint-plugin-import": "^2.26.0",
-    "eslint-plugin-jsdoc": "^61.5.0",
-    "eslint-plugin-jsx-a11y": "^6.5.1",
-    "eslint-plugin-matrix-org": "2.1.0",
-    "eslint-plugin-react": "^7.29.4",
-    "eslint-plugin-react-hooks": "^5.0.0",
-    "eslint-plugin-rxjs": "^5.0.3",
+    "eslint-plugin-element-call": "link:eslint",
     "eslint-plugin-storybook": "^10.3.6",
-    "eslint-plugin-unicorn": "^56.0.0",
     "fetch-mock": "11.1.5",
-    "global-jsdom": "^26.0.0",
-    "i18next": "^25.0.0",
+    "i18next": "^26.0.0",
     "i18next-browser-languagedetector": "^8.0.0",
     "i18next-cli": "^1.61.0",
     "jsdom": "^26.0.0",
@@ -114,16 +107,18 @@
     "livekit-client": "^2.18.1",
     "lodash-es": "^4.17.21",
     "loglevel": "^1.9.1",
-    "matrix-js-sdk": "github:matrix-org/matrix-js-sdk#develop",
-    "matrix-widget-api": "^1.16.1",
+    "matrix-js-sdk": "github:matrix-org/matrix-js-sdk#3f05dc4d104a3dfc753c5e3549a18c74fab4b076",
+    "matrix-widget-api": "^1.18.0",
     "node-stdlib-browser": "^1.3.1",
     "normalize.css": "^8.0.1",
-    "observable-hooks": "^4.2.3",
+    "oxfmt": "^0.66.0",
+    "oxlint": "^1.70.0",
+    "oxlint-tsgolint": "^0.25.0",
     "pako": "^2.0.4",
     "postcss": "^8.4.41",
     "postcss-preset-env": "^10.0.0",
-    "posthog-js": "1.374.0",
-    "prettier": "^3.0.0",
+    "postcss-selector-parser": "^7.1.1",
+    "posthog-js": "1.408.2",
     "qrcode": "^1.5.4",
     "react": "19",
     "react-dom": "19",
@@ -134,12 +129,10 @@
     "sass": "^1.42.1",
     "storybook": "^10.3.6",
     "typescript": "^5.8.3",
-    "typescript-eslint-language-service": "^5.0.5",
     "unique-names-generator": "^4.6.0",
     "uuid": "^14.0.0",
     "vaul": "^1.0.0",
     "vite": "^8.0.0",
-    "vite-plugin-generate-file": "^0.3.0",
     "vite-plugin-html": "^3.2.2",
     "vite-plugin-node-polyfills": "^0.28.0",
     "vite-plugin-node-stdlib-browser": "^0.2.1",
@@ -148,17 +141,5 @@
     "vitest": "^4.1.5",
     "vitest-axe": "^1.0.0-pre.3"
   },
-  "pnpm": {
-    "overrides": {
-      "@livekit/components-core>rxjs": "^7.8.1",
-      "@livekit/track-processors>@mediapipe/tasks-vision": "^0.10.18",
-      "minimatch": "^10.2.3",
-      "tar": "^7.5.11",
-      "glob": "^10.5.0",
-      "qs": "^6.14.1",
-      "js-yaml": "^4.1.1",
-      "esbuild": "^0.28.0"
-    }
-  },
-  "packageManager": "pnpm@10.33.0"
+  "packageManager": "pnpm@11.21.0+sha512.521705bce689924eac72f5a3587122f362689ef6571e55ba80076fd637c11132ecffada26fad4ea79c485bfddbfd3d5a2a5b05805a77e893de71ec8a6cca3bb1"
 }

playwright-backend-docker-compose.override.yml

@@ -1,7 +0,0 @@
-services:
-  synapse:
-    volumes:
-      - ./backend/playwright_homeserver.yaml:/data/cfg/homeserver.yaml:Z
-  synapse-1:
-    volumes:
-      - ./backend/playwright_homeserver-othersite.yaml:/data/cfg/homeserver.yaml:Z

playwright-backend-docker-compose.yml

@@ -1,2 +0,0 @@
-include:
-  - dev-backend-docker-compose.yml

playwright.config.ts

@@ -11,6 +11,9 @@ import { join } from "path";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
 
+import { COMPONENT_HARNESS_URL } from "./playwright/component/harness.ts";
+import { SDK_HARNESS_URL } from "./playwright/sdk/harness.ts";
+
 const baseURL = process.env.USE_DOCKER
   ? "http://localhost:8080"
   : "https://localhost:3000";
@@ -36,8 +39,20 @@ export default defineConfig({
   retries: process.env.CI ? 2 : 0,
   /* Opt out of parallel tests on CI. */
   workers: process.env.CI ? 1 : undefined,
-  /* Reporter to use. See https://playwright.dev/docs/test-reporters */
-  reporter: "html",
+  /**
+   * Reporter to use. See https://playwright.dev/docs/test-reporters
+   *
+   * On CI, `list` prints a line per test as it finishes, which keeps the job
+   * log moving; `github` annotates failures on the PR; `html` is uploaded as
+   * an artifact and must never try to open a browser there.
+   */
+  reporter: process.env.CI
+    ? [["list"], ["github"], ["html", { open: "never" }]]
+    : [["list"], ["html"]],
+  /* Stop a broken run early on CI instead of waiting out every retry. */
+  maxFailures: process.env.CI ? 5 : undefined,
+  /* Under the job's 60 minute limit, so a hung run still ends with a report. */
+  globalTimeout: process.env.CI ? 50 * 60 * 1000 : undefined,
   /* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
   use: {
     /* Base URL to use in actions like `await page.goto('/')`. */
@@ -84,6 +99,11 @@ export default defineConfig({
             // enumerateDevices work on CI runners without real hardware.
             "media.navigator.streams.fake": true,
             "media.navigator.permission.disabled": true,
+            // Vite serves HTTPS over HTTP/2, and Firefox intermittently stalls
+            // on Node's HTTP/2 server with a page that never finishes loading
+            // (one run in five or so, locally). Every server in the suite
+            // still speaks HTTP/1.1, so nothing is lost by insisting on it.
+            "network.http.http2.enabled": false,
           },
         },
       },
@@ -115,14 +135,41 @@ export default defineConfig({
   ],
 
   /* Run your local dev server before starting the tests */
-  webServer: {
-    command: "./scripts/playwright-webserver-command.sh",
-    url: baseURL,
-    reuseExistingServer: !process.env.CI,
-    ignoreHTTPSErrors: true,
-    gracefulShutdown: {
-      signal: "SIGTERM",
-      timeout: 500,
+  webServer: [
+    {
+      command: "./scripts/playwright-webserver-command.sh",
+      url: baseURL,
+      reuseExistingServer: !process.env.CI,
+      ignoreHTTPSErrors: true,
+      gracefulShutdown: {
+        signal: "SIGTERM",
+        timeout: 500,
+      },
     },
-  },
+    {
+      // The harness that embeds Element Call as a component. Always a Vite dev
+      // server, whether or not the app itself is being served from Docker,
+      // since there is nothing to build: it is a development page only.
+      command: "pnpm dev:component",
+      url: COMPONENT_HARNESS_URL,
+      reuseExistingServer: !process.env.CI,
+      ignoreHTTPSErrors: true,
+      gracefulShutdown: {
+        signal: "SIGTERM",
+        timeout: 500,
+      },
+    },
+    {
+      // The harness that uses the MatrixRTC SDK without Element Call. A Vite
+      // dev server for the same reason as the component's.
+      command: "pnpm dev:sdk",
+      url: SDK_HARNESS_URL,
+      reuseExistingServer: !process.env.CI,
+      ignoreHTTPSErrors: true,
+      gracefulShutdown: {
+        signal: "SIGTERM",
+        timeout: 500,
+      },
+    },
+  ],
 });

playwright/audio-menu.spec.ts

@@ -0,0 +1,229 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, test, type Locator, type Page } from "@playwright/test";
+
+import { SpaHelpers } from "./spa-helpers.ts";
+import { installFakeDevices } from "./utils/fake-devices.ts";
+
+test.describe("the quick audio menu", () => {
+  test("lists speakers and microphones with a live level meter", async ({
+    page,
+  }) => {
+    await installFakeDevices(page, { microphones: 3, speakers: 3 });
+    await joinACall(page, "Menu user", "Audio menu");
+    await openAudioMenu(page);
+
+    await expect(page.getByRole("group", { name: "Speaker" })).toBeVisible();
+    await expect(page.getByRole("group", { name: "Microphone" })).toBeVisible();
+    // By name, not count: the browser adds its own fake output and a Default.
+    for (const n of [1, 2, 3])
+      await expect(
+        page
+          .getByRole("group", { name: "Speaker" })
+          .getByRole("menuitemradio", { name: `Fake Speaker ${n}` }),
+      ).toBeVisible();
+
+    await expect(
+      page.getByRole("menuitemradio", { checked: true }),
+    ).toHaveCount(2);
+    const meter = page.getByRole("meter", { name: "Microphone level" });
+    await expect(meter).toBeVisible();
+    await expect(meter).toHaveAttribute("aria-valuenow", /\d+/);
+    await expect(meter).toHaveAttribute("aria-valuetext", /\d+ of \d+/);
+
+    // Both browsers here can route audio; the platform that can't is a unit check.
+    await expect(
+      page
+        .getByRole("group", { name: "Speaker" })
+        .getByRole("menuitemradio")
+        .first(),
+    ).toHaveAttribute("aria-disabled", "false");
+  });
+
+  test("moves the microphone and the speaker without disturbing the call", async ({
+    browser,
+  }) => {
+    // Two browsers and a real call.
+    test.slow();
+    const hostContext = await browser.newContext({ reducedMotion: "reduce" });
+    const host = await hostContext.newPage();
+    await installFakeDevices(host, { microphones: 3, speakers: 3 });
+    await joinACall(host, "Host", "Device switch");
+
+    const inviteLink = await SpaHelpers.getCallInviteLink(host);
+    const guestContext = await browser.newContext({ reducedMotion: "reduce" });
+    const guest = await guestContext.newPage();
+    await SpaHelpers.joinCallFromInviteLink(guest, inviteLink, "Guest");
+    await SpaHelpers.expectVideoTilesCount(guest, 2);
+
+    await openAudioMenu(host);
+    await selectDevice(host, "Microphone", "Fake Microphone 2");
+    await openAudioMenu(host);
+    await selectDevice(host, "Speaker", "Fake Speaker 2");
+
+    // Not a rejoin: neither side drops, and the guest still has both tiles.
+    await expect(
+      host.getByRole("dialog", { name: "Reconnecting…" }),
+    ).not.toBeVisible();
+    await expect(
+      guest.getByRole("dialog", { name: "Reconnecting…" }),
+    ).not.toBeVisible();
+    await SpaHelpers.expectVideoTilesCount(guest, 2);
+    await expect(guest.getByText("Waiting for media...")).not.toBeVisible();
+
+    await hostContext.close();
+    await guestContext.close();
+  });
+
+  test("keeps the meter moving while muted, and sends nothing", async ({
+    browser,
+  }) => {
+    // Two browsers and a real call.
+    test.slow();
+    const hostContext = await browser.newContext({ reducedMotion: "reduce" });
+    const host = await hostContext.newPage();
+    await installFakeDevices(host);
+    await joinACall(host, "Muted host", "Muted meter");
+
+    const inviteLink = await SpaHelpers.getCallInviteLink(host);
+    const guestContext = await browser.newContext({ reducedMotion: "reduce" });
+    const guest = await guestContext.newPage();
+    await SpaHelpers.joinCallFromInviteLink(guest, inviteLink, "Listener");
+    await SpaHelpers.expectVideoTilesCount(guest, 2);
+
+    const mute = host.getByTestId("incall_mute");
+    await mute.click();
+    await expect(mute).toHaveAttribute("aria-checked", "false");
+    await openAudioMenu(host);
+
+    const meter = host.getByRole("meter", { name: "Microphone level" });
+    await expect(meter).toBeVisible();
+    // By test id: the modal menu hides the rest of the call from the a11y tree.
+    await expect(mute).toHaveAttribute("aria-checked", "false");
+    await expect(mute).toBeVisible();
+    // And the guest is shown the mute.
+    await expect(
+      guest.getByTestId("videoTile").filter({ hasText: "Muted host" }),
+    ).toBeVisible();
+
+    await hostContext.close();
+    await guestContext.close();
+  });
+
+  test("keeps the meter at the foot of the list while it scrolls", async ({
+    page,
+  }) => {
+    await installFakeDevices(page, { microphones: 20, speakers: 4 });
+    await joinACall(page, "Scroller", "Long device list");
+    await openAudioMenu(page);
+
+    const meter = page.getByRole("meter", { name: "Microphone level" });
+    await expect(meter).toBeVisible();
+
+    // Scrolled so the microphones start at the top: only there does a pinned
+    // meter differ from one that is simply last.
+    const list = page.locator("[role='menu'] div[role='none']").first();
+    await list.evaluate((element) => {
+      const group = element.querySelector("[role='group'][aria-label*='icro']");
+      element.scrollTop +=
+        group!.getBoundingClientRect().top -
+        element.getBoundingClientRect().top;
+    });
+
+    await expect(meter).toBeInViewport();
+    await expectPinnedInside(meter, list);
+    await expect(
+      page.getByRole("menuitemradio", { name: "Fake Microphone 20" }),
+    ).toBeVisible();
+  });
+
+  test("shows the focus ring only when the keyboard moved the focus", async ({
+    page,
+    browserName,
+  }) => {
+    test.skip(
+      browserName === "firefox",
+      "Headless Firefox does not deliver synthetic key presses reliably; see reconnect.spec.ts",
+    );
+    await installFakeDevices(page);
+    await joinACall(page, "Keyboard user", "Focus ring");
+    await openAudioMenu(page);
+
+    const first = page.getByRole("menuitemradio").first();
+    // Opened by pointer: no ring, though Radix has moved focus into the menu.
+    await expect.poll(async () => outlineWidth(first)).toBe(0);
+
+    await page.keyboard.press("ArrowDown");
+    const focused = page.locator("[role='menuitemradio']:focus");
+    await expect.poll(async () => outlineWidth(focused)).toBeGreaterThan(0);
+
+    // And the pointer takes it away again.
+    await first.hover();
+    await expect.poll(async () => outlineWidth(focused)).toBe(0);
+  });
+});
+
+/** Creates a call and joins it, leaving the page in the call. */
+async function joinACall(
+  page: Page,
+  userName: string,
+  callName: string,
+): Promise<void> {
+  await page.goto("/");
+  await SpaHelpers.createCall(page, userName, callName, true);
+  await expect(page.getByTestId("name_tag")).toContainText(userName);
+  // The media controls stay disabled until devices have enumerated.
+  await expect(page.getByTestId("incall_mute")).toBeEnabled({
+    timeout: 10_000,
+  });
+}
+
+async function openAudioMenu(page: Page): Promise<void> {
+  await page.getByRole("button", { name: "Microphone" }).click();
+  await expect(page.getByRole("menu")).toBeVisible();
+}
+
+async function selectDevice(
+  page: Page,
+  section: "Speaker" | "Microphone",
+  name: string,
+): Promise<void> {
+  const item = page
+    .getByRole("group", { name: section })
+    .getByRole("menuitemradio", { name });
+  await item.click();
+  // Selecting doesn't close the menu, so dismiss it.
+  await page.keyboard.press("Escape");
+  await expect(page.getByRole("menu")).not.toBeVisible();
+}
+
+/** Asserts the meter sits within the scrollport and inside the menu's frame. */
+async function expectPinnedInside(
+  meter: Locator,
+  list: Locator,
+): Promise<void> {
+  const meterBox = (await meter.boundingBox())!;
+  const listBox = (await list.boundingBox())!;
+  const frame = (await meter.page().getByRole("menu").boundingBox())!;
+
+  expect(meterBox.y + meterBox.height).toBeLessThanOrEqual(
+    listBox.y + listBox.height + 1,
+  );
+  expect(meterBox.y).toBeGreaterThanOrEqual(listBox.y - 1);
+  expect(meterBox.x).toBeGreaterThan(frame.x);
+  expect(meterBox.x + meterBox.width).toBeLessThan(frame.x + frame.width);
+}
+
+/** Painted outline width, in px. */
+async function outlineWidth(item: Locator): Promise<number> {
+  if ((await item.count()) === 0) return 0;
+  return item.first().evaluate((element) => {
+    const { outlineStyle, outlineWidth } = getComputedStyle(element);
+    return outlineStyle === "none" ? 0 : Number.parseFloat(outlineWidth) || 0;
+  });
+}

playwright/component/audio-menu.spec.ts

@@ -0,0 +1,135 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, type Locator, type Page, test } from "@playwright/test";
+
+import { createUserAndRoom, resizeContainer, startHarness } from "./harness.ts";
+import { installFakeDevices } from "../utils/fake-devices.ts";
+
+/**
+ * The device menu with Element Call as a component in a host page, where the
+ * portalled menu must be sized against the call, not the window. Driven from
+ * the lobby: it builds the same menu, without two connections' worth of flake.
+ */
+
+// Sign-in, crypto setup and sync happen twice before anything shows.
+test.describe.configure({ timeout: 180_000 });
+
+test("sizes the device list against the call, not the window", async ({
+  page,
+}) => {
+  await installFakeDevices(page, { microphones: 20, speakers: 4 });
+  const { username, roomId } = await createUserAndRoom("menusize");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+
+  // A short call in a much taller page.
+  const container = pane.getByTestId("call-container");
+  await resizeContainer(container, { width: 900, height: 400 });
+  await expect(pane.getByTestId("lobby_joinCall")).toBeVisible({
+    timeout: 60_000,
+  });
+
+  const list = await openDeviceList(page, pane);
+  const callHeight = (await container.boundingBox())!.height;
+  const windowHeight = page.viewportSize()!.height;
+  const listHeight = (await list.boundingBox())!.height;
+
+  expect(callHeight).toBeLessThan(windowHeight * 0.75);
+  expect(listHeight).toBeLessThanOrEqual(callHeight);
+  expect(listHeight).toBeLessThan(windowHeight * 0.6);
+});
+
+test("follows the call area when the host resizes it", async ({ page }) => {
+  await installFakeDevices(page, { microphones: 20, speakers: 4 });
+  const { username, roomId } = await createUserAndRoom("menuresize");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+
+  const container = pane.getByTestId("call-container");
+  await resizeContainer(container, { width: 900, height: 360 });
+  await expect(pane.getByTestId("lobby_joinCall")).toBeVisible({
+    timeout: 60_000,
+  });
+
+  const list = await openDeviceList(page, pane);
+  const whenShort = (await list.boundingBox())!.height;
+
+  // The host grows the call while the menu is open.
+  await resizeContainer(container, { width: 900, height: 700 });
+  await expect
+    .poll(async () => (await list.boundingBox())!.height)
+    .toBeGreaterThan(whenShort);
+});
+
+test("keeps every device reachable in a small container", async ({ page }) => {
+  await installFakeDevices(page, { microphones: 20, speakers: 4 });
+  const { username, roomId } = await createUserAndRoom("menureach");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+
+  const container = pane.getByTestId("call-container");
+  await resizeContainer(container, { width: 400, height: 360 });
+  await expect(pane.getByTestId("lobby_joinCall")).toBeVisible({
+    timeout: 60_000,
+  });
+
+  const list = await openDeviceList(page, pane);
+  // More devices than fit, so the list must scroll.
+  expect(await list.evaluate((el) => el.scrollHeight > el.clientHeight)).toBe(
+    true,
+  );
+
+  const last = page.getByRole("menuitemradio", { name: "Fake Microphone 20" });
+  await last.scrollIntoViewIfNeeded();
+  await expect(last).toBeInViewport();
+  // Reachable means clickable: the menu may be drawn outside the call area.
+  await last.click();
+  await expect(last).toHaveAttribute("aria-checked", "true");
+});
+
+test("tracks the focus source of its own call, not the page", async ({
+  page,
+}) => {
+  await installFakeDevices(page);
+  const { username, roomId } = await createUserAndRoom("menufocus");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+  const other = panes.nth(1);
+
+  await expect(pane.getByTestId("lobby_joinCall")).toBeVisible({
+    timeout: 60_000,
+  });
+  await openDeviceList(page, pane);
+  const menu = page.getByRole("menu");
+
+  // Asserted on the attribute: the component build's scoped stylesheet doesn't
+  // reach the portalled menu, so its ring can't be read here.
+  await expect(menu).toHaveAttribute("data-focus-source", "pointer");
+
+  // A key pressed in the other call says nothing about this menu.
+  await other.evaluate((element) =>
+    element.dispatchEvent(
+      new KeyboardEvent("keydown", { key: "ArrowDown", bubbles: true }),
+    ),
+  );
+  await expect(menu).toHaveAttribute("data-focus-source", "pointer");
+
+  await page.keyboard.press("ArrowDown");
+  await expect(menu).toHaveAttribute("data-focus-source", "keyboard");
+});
+
+/** Opens a component's microphone menu and returns its device list. */
+async function openDeviceList(page: Page, pane: Locator): Promise<Locator> {
+  await pane
+    .getByRole("button", { name: "Microphone" })
+    .click({ timeout: 60_000 });
+  await expect(page.getByRole("menu")).toBeVisible();
+  const list = page.getByRole("menu").getByTestId("device-list");
+  await expect(list).toBeVisible();
+  return list;
+}

playwright/component/component-call.spec.ts

@@ -0,0 +1,285 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, type Locator, type Page, test } from "@playwright/test";
+
+import {
+  createUserAndRoom,
+  expectWithin,
+  resizeContainer,
+  startHarness,
+} from "./harness.ts";
+import { SpaHelpers } from "../spa-helpers.ts";
+
+/**
+ * Element Call embedded as a React component, driven through the development
+ * harness in `component/dev`.
+ *
+ * What these cover that the widget tests cannot is everything that follows from
+ * sharing a page with a host: whether Element Call stays inside the space it
+ * was given, and whether two of it can exist at once. As a widget, the iframe
+ * guaranteed both.
+ */
+
+// Each test signs in twice, sets up crypto twice and syncs twice before
+// anything is on screen, and then waits for media to connect; the waits below
+// are sized for that, so the tests have to be too
+test.describe.configure({ timeout: 180_000 });
+
+/** The settings button, whichever of the two the footer is currently showing. */
+function settingsButton(pane: Locator): Locator {
+  return pane
+    .getByTestId("settings-bottom-left")
+    .or(pane.getByTestId("settings-bottom-center"))
+    .filter({ visible: true })
+    .first();
+}
+
+test("holds a call between two components on one page", async ({ page }) => {
+  const { username, roomId } = await createUserAndRoom("twocomponents");
+  const panes = await startHarness(page, username, roomId);
+
+  // Each component shows a lobby of its own, and neither has joined anything
+  // just by being rendered
+  for (const index of [0, 1])
+    await expect(panes.nth(index).getByTestId("lobby_joinCall")).toBeVisible({
+      timeout: 60_000,
+    });
+
+  for (const index of [0, 1])
+    await panes.nth(index).getByTestId("lobby_joinCall").click();
+
+  // Two devices of one account, so each component should see itself and the
+  // other. This is the part that proves two Element Calls in one page are two
+  // calls, and not one shared thing wearing two hats.
+  for (const index of [0, 1])
+    await expect(panes.nth(index).getByTestId("videoTile")).toHaveCount(2, {
+      timeout: 60_000,
+    });
+});
+
+test("keeps its modals inside the container it was given", async ({ page }) => {
+  const { username, roomId } = await createUserAndRoom("containment");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+  const container = pane.getByTestId("call-container");
+
+  // In the flat container the harness gives it by default, Element Call hides
+  // its controls a few seconds after the call starts, as it would in a flat
+  // window. A full-size container keeps them on screen to be clicked.
+  await resizeContainer(container, { width: 900, height: 640 });
+  await pane.getByTestId("lobby_joinCall").click({ timeout: 60_000 });
+  await expect(pane.getByTestId("footer-container")).toBeVisible({
+    timeout: 60_000,
+  });
+
+  // Both of these are positioned `fixed`, and were centred on the window
+  // rather than the container until it was made a containing block. The
+  // settings dialog spilled over the host's interface; the reaction picker sat
+  // at 82vh, which put it below the container entirely and so out of sight.
+  await settingsButton(pane).click();
+  await expectWithin(pane.getByRole("dialog"), container);
+  await pane.getByTestId("modal_close").click();
+
+  await pane.getByRole("button", { name: "Reactions" }).click();
+  await expectWithin(
+    pane.getByRole("dialog", { name: "Pick reaction" }),
+    container,
+  );
+});
+
+test("keeps the call inside the container, wherever the host put it", async ({
+  page,
+}) => {
+  const { username, roomId } = await createUserAndRoom("tileswithin");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+  const container = pane.getByTestId("call-container");
+
+  // Large enough for the layout switch to be offered
+  await resizeContainer(container, { width: 900, height: 640 });
+  await pane.getByTestId("lobby_joinCall").click({ timeout: 60_000 });
+  await expect(pane.getByTestId("footer-container")).toBeVisible({
+    timeout: 60_000,
+  });
+
+  // The spotlight layout draws its tile in the fixed grid, which is positioned
+  // against Element Call's root rather than laid out in flow. The harness puts
+  // the container below a header of its own, so a grid offset measured from
+  // the top of the page instead of from the root would land the tile on top of
+  // the footer and out of the bottom of the container.
+  await pane.getByRole("radio", { name: "Spotlight" }).check();
+  const tile = pane.getByTestId("videoTile").first();
+  await expect(tile).toBeVisible({ timeout: 60_000 });
+  await expectWithin(tile, container);
+});
+
+test("leaves the host's own page unstyled", async ({ page }) => {
+  const { username, roomId } = await createUserAndRoom("hoststyles");
+  const panes = await startHarness(page, username, roomId);
+  await expect(panes.first().getByTestId("lobby_joinCall")).toBeVisible({
+    timeout: 60_000,
+  });
+
+  // Element Call's stylesheet is written for a page of its own: normalize.css
+  // gives `html` a line height, Compound gives `body` its font and feature
+  // settings, and the design tokens live on `:root`. None of that may reach the
+  // host's document — the harness sets none of these itself, so anything other
+  // than the browser's defaults here came from us.
+  const host = await page.evaluate(() => {
+    const html = getComputedStyle(document.documentElement);
+    const body = getComputedStyle(document.body);
+    return {
+      lineHeight: html.lineHeight,
+      fontFeatureSettings: body.fontFeatureSettings,
+      token: html.getPropertyValue("--cpd-color-text-primary"),
+    };
+  });
+  expect(host).toEqual({
+    lineHeight: "normal",
+    fontFeatureSettings: "normal",
+    token: "",
+  });
+
+  // While inside the container, the same rules do apply
+  const root = panes.first().locator("[data-element-call-root]");
+  await expect(root).toHaveCSS("font-feature-settings", /"kern"/);
+});
+
+test("tells its host what it is doing", async ({ page }) => {
+  const { username, roomId } = await createUserAndRoom("hostbridge");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+  const log = page.getByTestId("bridge-log");
+
+  // Every component reports to its host through the bridge, whether that host
+  // is a widget container or an application embedding it directly
+  await expect(log).toContainText("contentLoaded", { timeout: 60_000 });
+
+  await pane.getByTestId("lobby_joinCall").click({ timeout: 60_000 });
+  await expect(log).toContainText("notifyJoined", { timeout: 60_000 });
+  await expect(log).toContainText("setAlwaysOnScreen(true)", {
+    timeout: 60_000,
+  });
+
+  // And takes instructions back: the host asking for a mute should come back
+  // as the component reporting the new state
+  await pane.getByRole("button", { name: "Mute" }).click();
+  await expect(log).toContainText("notifyDeviceMute(audio: false", {
+    timeout: 30_000,
+  });
+});
+
+test("lays itself out for the space it is given, not the page", async ({
+  page,
+}) => {
+  const { username, roomId } = await createUserAndRoom("containersize");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+  const container = pane.getByTestId("call-container");
+  const call = pane.locator("[data-layout]");
+
+  await pane.getByTestId("lobby_joinCall").click({ timeout: 60_000 });
+  await expect(call).toBeVisible({ timeout: 60_000 });
+  await expect(call).not.toHaveAttribute("data-layout", "pip");
+
+  // As a widget, Element Call's container and its window were one and the same:
+  // a host wanting a picture-in-picture made the iframe small, and Element Call
+  // saw the window shrink. A component gets no such signal from the window,
+  // which stays as large as it ever was; only the container changes.
+  await resizeContainer(container, { width: 300, height: 300 });
+  await expect(call).toHaveAttribute("data-layout", "pip");
+
+  await resizeContainer(container, { width: 900, height: 700 });
+  await expect(call).not.toHaveAttribute("data-layout", "pip");
+});
+
+/**
+ * The shape of a call at whatever size it has been given: the layout it chose,
+ * how much of the height the tile and the footer take, and which controls the
+ * footer shows. Two calls with the same shape look the same, participants aside.
+ */
+async function callShape(scope: Page | Locator): Promise<{
+  layout: string | null;
+  tileHeight: number;
+  footerHeight: number;
+  buttons: (string | null)[];
+}> {
+  const call = scope.locator("[data-layout]");
+  const footer = scope.getByTestId("footer-container");
+  await expect(footer).toBeVisible();
+  // The tile arrives with the media connection, which can take a while
+  const tile = scope.getByTestId("videoTile").first();
+  await expect(tile).toBeVisible({ timeout: 60_000 });
+  const tileBox = (await tile.boundingBox())!;
+  const footerBox = (await footer.boundingBox())!;
+  // Buttons and switches alike: the mute controls are switches
+  const buttons = await footer
+    .locator("button")
+    .filter({ visible: true })
+    .evaluateAll((elements) =>
+      elements.map((element) => element.getAttribute("aria-label")),
+    );
+  return {
+    layout: await call.getAttribute("data-layout"),
+    tileHeight: Math.round(tileBox.height),
+    footerHeight: Math.round(footerBox.height),
+    buttons,
+  };
+}
+
+test("looks the same in a small container as in a small window", async ({
+  page,
+  browser,
+}) => {
+  // Two calls to set up, one of them through the harness's two logins
+  test.setTimeout(300_000);
+  const size = { width: 300, height: 300 };
+
+  // The reference is Element Call owning a window of that size, which is what
+  // a mobile app's webview or a browser's picture-in-picture gives it, and
+  // what its small-window styling was written for.
+  // No permissions to grant: each browser is launched with fake media that is
+  // handed out without asking (see playwright.config.ts), and Firefox rejects
+  // a request for `camera` or `microphone` outright
+  const referenceContext = await browser.newContext({
+    viewport: size,
+    ignoreHTTPSErrors: true,
+  });
+  const referencePage = await referenceContext.newPage();
+  await referencePage.goto("/");
+  await SpaHelpers.createCall(referencePage, "Reference", "smallwindow", true);
+  const reference = await callShape(referencePage);
+  await referencePage.screenshot({
+    path: test.info().outputPath("small-window.png"),
+  });
+
+  // The component gets a container of that size, in a window that is far larger
+  const { username, roomId } = await createUserAndRoom("smallcontainer");
+  const panes = await startHarness(page, username, roomId);
+  const pane = panes.first();
+  const container = pane.getByTestId("call-container");
+  await resizeContainer(container, size);
+  await pane.getByTestId("lobby_joinCall").click({ timeout: 60_000 });
+  await expect(pane.locator("[data-layout]")).toBeVisible({ timeout: 60_000 });
+  const component = await callShape(pane);
+  await container.screenshot({
+    path: test.info().outputPath("small-container.png"),
+  });
+  await referenceContext.close();
+
+  // The breakpoints in Element Call's stylesheets are container queries, so a
+  // small container gets the compact footer a small window does, rather than
+  // the full-width one the window's own size would call for
+  expect(component).toEqual(reference);
+  // And that footer is the compact one: a single row of controls, not the
+  // full-height bar with its logo and layout switch that a large window gets
+  expect(component.footerHeight).toBeLessThan(size.height / 3);
+  expect(component.tileHeight + component.footerHeight).toBeLessThanOrEqual(
+    size.height,
+  );
+});

playwright/component/harness.ts

@@ -0,0 +1,132 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, type Locator, type Page } from "@playwright/test";
+
+import { SynapseAdmin } from "../utils/synapse-admin.ts";
+
+/**
+ * Where the component harness is served — `component/dev`, which embeds Element
+ * Call the way a host application would. Not the `baseURL` the rest of the
+ * suite uses: these tests drive a page that contains Element Call rather than
+ * Element Call itself.
+ */
+export const COMPONENT_HARNESS_URL = "https://localhost:3001";
+
+const HOMESERVER_URL = "https://synapse.m.localhost";
+const PASSWORD = "foobarbaz1!";
+
+/**
+ * Registers a user through the Synapse admin API and creates a room for it to
+ * call in, without touching a browser. The harness signs into this account
+ * twice, giving two devices in one page and so a real call between the two
+ * components.
+ */
+export async function createUserAndRoom(
+  name: string,
+): Promise<{ username: string; roomId: string }> {
+  const username = `${name}_${Date.now()}`;
+  const { access_token: accessToken } = await SynapseAdmin.forHomeserver(
+    HOMESERVER_URL,
+  ).registerUser(username, PASSWORD, name);
+
+  const response = await fetch(
+    `${HOMESERVER_URL}/_matrix/client/v3/createRoom`,
+    {
+      method: "POST",
+      headers: {
+        Authorization: `Bearer ${accessToken}`,
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({ name: `${name}'s call`, preset: "private_chat" }),
+    },
+  );
+  if (!response.ok)
+    throw new Error(
+      `Could not create a room: ${response.status} ${await response.text()}`,
+    );
+  const { room_id: roomId } = (await response.json()) as { room_id: string };
+
+  return { username, roomId };
+}
+
+/**
+ * Opens the harness signed in as the given user, and waits for both embedded
+ * calls to appear.
+ *
+ * @returns The two containers the host gave Element Call, in order.
+ */
+export async function startHarness(
+  page: Page,
+  username: string,
+  roomId: string,
+): Promise<Locator> {
+  const query = new URLSearchParams({
+    homeserver: HOMESERVER_URL,
+    username,
+    password: PASSWORD,
+    room: roomId,
+  });
+  await page.goto(`${COMPONENT_HARNESS_URL}/?${query.toString()}`);
+  await page.getByRole("button", { name: "Start" }).click();
+
+  const panes = page.getByTestId("call-pane");
+  // Two logins, two crypto setups and two initial syncs happen first
+  await expect(panes).toHaveCount(2, { timeout: 120_000 });
+  return panes;
+}
+
+/**
+ * Asserts that one element is drawn entirely inside another.
+ *
+ * This is the check that being a component rather than an iframe costs us: an
+ * iframe could not paint outside itself whatever its stylesheets said, whereas
+ * a component shares the page and has to be made to stay put.
+ */
+export async function expectWithin(
+  inner: Locator,
+  outer: Locator,
+): Promise<void> {
+  await expect(inner).toBeVisible();
+  // Wait for animations to settle.
+  await inner.evaluate(async (element) => {
+    for (const animation of element.getAnimations({ subtree: true }))
+      await animation.finished;
+  });
+
+  const innerBox = await inner.boundingBox();
+  const outerBox = await outer.boundingBox();
+  if (innerBox === null || outerBox === null)
+    throw new Error("Expected both elements to be laid out");
+
+  // A pixel of slack, for subpixel layout
+  const slack = 1;
+  expect(innerBox.x).toBeGreaterThanOrEqual(outerBox.x - slack);
+  expect(innerBox.y).toBeGreaterThanOrEqual(outerBox.y - slack);
+  expect(innerBox.x + innerBox.width).toBeLessThanOrEqual(
+    outerBox.x + outerBox.width + slack,
+  );
+  expect(innerBox.y + innerBox.height).toBeLessThanOrEqual(
+    outerBox.y + outerBox.height + slack,
+  );
+}
+
+/**
+ * Gives one of the harness's containers a new size. Element Call lays itself
+ * out for the size of its container, so this is how a test puts it into a
+ * particular mode: a flat or narrow one, a picture-in-picture, or a full-size
+ * window, without the window itself changing at all.
+ */
+export async function resizeContainer(
+  container: Locator,
+  size: { width: number; height: number },
+): Promise<void> {
+  await container.evaluate((element, { width, height }) => {
+    element.style.width = `${width}px`;
+    element.style.height = `${height}px`;
+  }, size);
+}

playwright/errors.spec.ts

@@ -7,7 +7,7 @@ Please see LICENSE in the repository root for full details.
 
 import { expect, test } from "@playwright/test";
 
-import { createJTWToken } from "./fixtures/jwt-token";
+import { createJWTToken } from "./fixtures/jwt-token";
 
 test("Should show error screen if fails to get JWT token", async ({ page }) => {
   await page.goto("/");
@@ -95,7 +95,7 @@ test("Should show error screen if call creation is restricted", async ({
         contentType: "application/json",
         body: JSON.stringify({
           url: "wss://badurltotricktest/livekit/sfu",
-          jwt: createJTWToken("@fake:user", "!fake:room"),
+          jwt: createJWTToken("@fake:user", "!fake:room"),
         }),
       }),
   );

playwright/fixtures/jwt-token.ts

@@ -5,7 +5,7 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-export function createJTWToken(sub: string, room: string): string {
+export function createJWTToken(sub: string, room: string): string {
   return [
     {}, // header
     {

playwright/fixtures/widget-user.ts

@@ -109,10 +109,15 @@ export const widgetTest = test.extend<MyFixtures>({
       await TestHelpers.dismissInviteUnknownUserModal(ewPage1);
 
       // Accept the invite
+      await TestHelpers.closeReleaseAnnouncement(
+        ewPage2,
+        "Introducing Sections",
+      );
+      await TestHelpers.expandAllSections(ewPage2);
       await expect(
-        ewPage2.getByRole("option", { name: "Welcome Room" }),
+        TestHelpers.roomListItem(ewPage2, "Welcome Room"),
       ).toBeVisible();
-      await ewPage2.getByRole("option", { name: "Welcome Room" }).click();
+      await TestHelpers.roomListItem(ewPage2, "Welcome Room").click();
       await ewPage2.getByRole("button", { name: "Accept" }).click();
       await expect(
         ewPage2
@@ -120,9 +125,14 @@ export const widgetTest = test.extend<MyFixtures>({
           .getByRole("heading", { name: "Welcome Room" }),
       ).toBeVisible();
     } else if (callType === "dm") {
+      await TestHelpers.closeReleaseAnnouncement(
+        ewPage1,
+        "Introducing Sections",
+      );
+
       await ewPage1
         .getByRole("navigation", { name: "Room list" })
-        .getByRole("button", { name: "New conversation" })
+        .getByRole("button", { name: "New", exact: true })
         .click();
 
       await ewPage1.getByRole("menuitem", { name: "Start chat" }).click();
@@ -147,8 +157,12 @@ export const widgetTest = test.extend<MyFixtures>({
       ).toBeVisible();
 
       // Accept the DM invite from brooks
-      // This how playwright record selects the DM invite in the room list
-      await ewPage2.getByRole("option", { name: "Open room" }).click();
+      await TestHelpers.closeReleaseAnnouncement(
+        ewPage2,
+        "Introducing Sections",
+      );
+      await TestHelpers.expandAllSections(ewPage2);
+      await TestHelpers.roomListItem(ewPage2, brooksDisplayName).click();
       await ewPage2.getByRole("button", { name: "Start chatting" }).click();
     }
 

playwright/reconnect.spec.ts

@@ -7,6 +7,8 @@ Please see LICENSE in the repository root for full details.
 
 import { expect, test } from "@playwright/test";
 
+import { SpaHelpers } from "./spa-helpers";
+
 // Skip test for Firefox, due to page.keyboard.press("Tab") not reliable on headless mode
 test.skip(
   ({ browserName }) => browserName === "firefox",
@@ -17,6 +19,12 @@ test("can only interact with header and footer while reconnecting", async ({
   page,
 }) => {
   await page.goto("/");
+
+  // The reconnecting state is entered via the probablyLeft timer, which
+  // mirrors the delayed leave event's timeout. With delegation that timeout
+  // is one hour, putting it out of reach of the clock fast-forward below.
+  // Keep the leave client-managed so its short timeout applies.
+  await SpaHelpers.disableLeaveDelegation(page);
   await page.getByTestId("home_callName").click();
   await page.getByTestId("home_callName").fill("Test call");
   await page.getByTestId("home_displayName").click();

playwright/sdk/data.spec.ts

@@ -0,0 +1,41 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, test } from "@playwright/test";
+
+import { startPair, tileOf } from "./harness";
+
+test.describe.configure({ timeout: 300_000 });
+
+test("a message sent beside the media reaches the peer, and only the peer", async ({
+  browser,
+}) => {
+  const { pages, users } = await startPair(browser, "sdkdata");
+  const [sender, receiver] = pages;
+  // Both are in the call before anything is sent, so the receiver knows the
+  // sender as a member and does not drop the message
+  for (const page of pages)
+    await expect(page.getByTestId("member")).toHaveCount(2, {
+      timeout: 60_000,
+    });
+  await expect(tileOf(receiver, users[0])).toBeVisible();
+
+  await sender.getByPlaceholder("message").fill("hello from the SDK");
+  await sender.getByRole("button", { name: "Send" }).click();
+
+  const message = receiver.getByTestId("message");
+  await expect(message).toHaveText(
+    `${users[0].displayName}: hello from the SDK`,
+    {
+      timeout: 30_000,
+    },
+  );
+  await expect(message).toHaveAttribute("data-topic", "chat");
+  await expect(message).toHaveAttribute("data-user-id", users[0].userId);
+  // Our own messages are not echoed back
+  await expect(sender.getByTestId("message")).toHaveCount(0);
+});

playwright/sdk/harness.ts

@@ -0,0 +1,167 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import {
+  type Browser,
+  expect,
+  type Locator,
+  type Page,
+} from "@playwright/test";
+
+import { SynapseAdmin } from "../utils/synapse-admin.ts";
+
+/**
+ * Where the SDK harness is served — `sdk/dev`, a page that uses the SDK the way
+ * a host would, with none of Element Call in it.
+ */
+export const SDK_HARNESS_URL = "https://localhost:3002";
+
+const HOMESERVER_URL = "https://synapse.m.localhost";
+const PASSWORD = "foobarbaz1!";
+
+/** A registered user, with the session the registration opened. */
+export interface User {
+  username: string;
+  displayName: string;
+  userId: string;
+  deviceId: string;
+  accessToken: string;
+}
+
+/**
+ * Registers two users through the Synapse admin API and has the first create a
+ * public room, so that the second can join it by id without an invite. The
+ * registration logs each user in, which spares the harness a `/login` call
+ * that the homeserver rate-limits.
+ */
+export async function createUsersAndRoom(
+  name: string,
+): Promise<{ users: [User, User]; roomId: string }> {
+  const admin = SynapseAdmin.forHomeserver(HOMESERVER_URL);
+  const users = (await Promise.all(
+    ["a", "b"].map(async (letter, index): Promise<User> => {
+      const username = `${name}_${letter}_${Date.now()}`;
+      const displayName = `${name} ${"AB"[index]}`;
+      const registration = await admin.registerUser(
+        username,
+        PASSWORD,
+        displayName,
+      );
+      return {
+        username,
+        displayName,
+        userId: registration.user_id,
+        deviceId: registration.device_id,
+        accessToken: registration.access_token,
+      };
+    }),
+  )) as [User, User];
+
+  const response = await fetch(
+    `${HOMESERVER_URL}/_matrix/client/v3/createRoom`,
+    {
+      method: "POST",
+      headers: {
+        Authorization: `Bearer ${users[0].accessToken}`,
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({
+        name: `${name}'s session`,
+        preset: "public_chat",
+        // Per-participant media keys travel in encrypted to-device messages,
+        // which only reach devices the sender's crypto tracks, and it tracks
+        // the members of encrypted rooms
+        initial_state: [
+          {
+            type: "m.room.encryption",
+            state_key: "",
+            content: { algorithm: "m.megolm.v1.aes-sha2" },
+          },
+        ],
+        // Every member has to be allowed to write its own membership, which
+        // a public room does not grant by default; the same levels Element
+        // Call gives a room it creates for a call
+        power_level_content_override: {
+          state_default: 0,
+          events_default: 0,
+          users_default: 0,
+          events: { "org.matrix.msc3401.call.member": 0 },
+        },
+      }),
+    },
+  );
+  if (!response.ok)
+    throw new Error(
+      `Could not create a room: ${response.status} ${await response.text()}`,
+    );
+  const { room_id: roomId } = (await response.json()) as { room_id: string };
+
+  return { users, roomId };
+}
+
+/**
+ * Opens the harness signed in as the given user and waits until the SDK
+ * reports the session as connected. The status line carries the SDK's error
+ * if it does not get there, so the failure says why.
+ */
+export async function startHarness(
+  page: Page,
+  user: User,
+  roomId: string,
+): Promise<void> {
+  const query = new URLSearchParams({
+    homeserver: HOMESERVER_URL,
+    accessToken: user.accessToken,
+    userId: user.userId,
+    deviceId: user.deviceId,
+    room: roomId,
+  });
+  await page.goto(`${SDK_HARNESS_URL}/?${query.toString()}`);
+  await page.getByRole("button", { name: "Start" }).click();
+  await waitForConnected(page);
+}
+
+/**
+ * A login, a crypto setup and an initial sync happen before the session can
+ * connect. An error is final, so it is not worth waiting out the timeout for
+ * "connected" after one.
+ */
+export async function waitForConnected(page: Page): Promise<void> {
+  const status = page.getByTestId("status");
+  await expect(status).toHaveText(/^(connected|Error)/, { timeout: 120_000 });
+  const text = await status.textContent();
+  if (text !== "connected")
+    throw new Error(`The harness did not connect to the session: ${text}`);
+}
+
+/**
+ * A context of its own per user, since a browser profile holds one login. No
+ * permissions to grant: each browser is launched with fake media that is
+ * handed out without asking (see playwright.config.ts).
+ */
+export async function newPage(browser: Browser): Promise<Page> {
+  const context = await browser.newContext({ ignoreHTTPSErrors: true });
+  return context.newPage();
+}
+
+/** Two users in one session, each on a page of their own. */
+export async function startPair(
+  browser: Browser,
+  name: string,
+): Promise<{ pages: [Page, Page]; users: [User, User]; roomId: string }> {
+  const { users, roomId } = await createUsersAndRoom(name);
+  const pages = await Promise.all([newPage(browser), newPage(browser)]);
+  await Promise.all(
+    pages.map(async (page, i) => startHarness(page, users[i], roomId)),
+  );
+  return { pages: pages as [Page, Page], users, roomId };
+}
+
+/** The tile a page shows for a user. */
+export function tileOf(page: Page, user: User): Locator {
+  return page.locator(`[data-testid="member"][data-user-id="${user.userId}"]`);
+}

playwright/sdk/lifecycle.spec.ts

@@ -0,0 +1,67 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { expect, test } from "@playwright/test";
+
+import { startPair, tileOf, waitForConnected } from "./harness.ts";
+
+/**
+ * Members coming and going: a member that leaves disappears for the peer, one
+ * that comes back is shown again, and the harness is left in the state its
+ * status line claims.
+ */
+
+test.describe.configure({ timeout: 300_000 });
+
+test("a member that leaves disappears for the peer", async ({ browser }) => {
+  const {
+    pages: [leaver, stayer],
+    users: [leaving, staying],
+  } = await startPair(browser, "sdkleave");
+  await expect(stayer.getByTestId("member")).toHaveCount(2, {
+    timeout: 60_000,
+  });
+
+  await leaver.getByRole("button", { name: "Leave" }).click();
+  await expect(leaver.getByTestId("status")).toHaveText("Left");
+  await expect(leaver.getByTestId("member")).toHaveCount(0);
+
+  await expect(tileOf(stayer, leaving)).toHaveCount(0, { timeout: 60_000 });
+  await expect(tileOf(stayer, staying)).toHaveCount(1);
+  await expect(stayer.getByTestId("status")).toHaveText("connected");
+});
+
+test("a member that reloads is shown again with its media", async ({
+  browser,
+}) => {
+  const {
+    pages: [reloader, watcher],
+    users: [reloading],
+  } = await startPair(browser, "sdkreload");
+  await expect(watcher.getByTestId("member")).toHaveCount(2, {
+    timeout: 60_000,
+  });
+
+  // The page comes back on the same device, so the new membership replaces
+  // the old one rather than sitting next to it
+  await reloader.reload();
+  await reloader.getByRole("button", { name: "Start" }).click();
+  await waitForConnected(reloader);
+
+  await expect(tileOf(watcher, reloading)).toHaveCount(1, {
+    timeout: 120_000,
+  });
+  const video = tileOf(watcher, reloading).locator("video");
+  await expect
+    .poll(async () => video.evaluate((v: HTMLVideoElement) => v.videoWidth), {
+      timeout: 60_000,
+    })
+    .toBeGreaterThan(0);
+  await expect(reloader.getByTestId("member")).toHaveCount(2, {
+    timeout: 60_000,
+  });
+});