diff --git a/src/settings/DeveloperSettingsTab.test.tsx b/src/settings/DeveloperSettingsTab.test.tsx
index 7bdf7091..51255666 100644
--- a/src/settings/DeveloperSettingsTab.test.tsx
+++ b/src/settings/DeveloperSettingsTab.test.tsx
@@ -5,13 +5,17 @@ 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, vi } from "vitest";
-import { render, waitFor } from "@testing-library/react";
+import { afterEach, describe, expect, it, type Mock, vi } from "vitest";
+import { render, waitFor, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { TooltipProvider } from "@vector-im/compound-web";
 
 import type { MatrixClient } from "matrix-js-sdk";
 import type { Room as LivekitRoom } from "livekit-client";
+// import { DeveloperSettingsTab } from "./DeveloperSettingsTab";
 import { DeveloperSettingsTab } from "./DeveloperSettingsTab";
-
+import { getSFUConfigWithOpenID } from "../livekit/openIDSFU";
+import { customLivekitUrl as customLivekitUrlSetting } from "./settings";
 // Mock url params hook to avoid environment-dependent snapshot churn.
 vi.mock("../UrlParams", () => ({
   useUrlParams: (): { mocked: boolean; answer: number } => ({
@@ -20,6 +24,14 @@ vi.mock("../UrlParams", () => ({
   }),
 }));
 
+// IMPORTANT: mock the same specifier used by DeveloperSettingsTab
+vi.mock("../livekit/openIDSFU", () => ({
+  getSFUConfigWithOpenID: vi.fn().mockResolvedValue({
+    url: "mock-url",
+    jwt: "mock-jwt",
+  }),
+}));
+
 // Provide a minimal mock of a Livekit Room structure used by the component.
 function createMockLivekitRoom(
   wsUrl: string,
@@ -52,30 +64,30 @@ function createMockMatrixClient(): MatrixClient {
 }
 
 describe("DeveloperSettingsTab", () => {
+  const livekitRooms: {
+    room: LivekitRoom;
+    url: string;
+    isLocal?: boolean;
+  }[] = [
+    createMockLivekitRoom(
+      "wss://local-sfu.example.org",
+      { region: "local", version: "1.2.3" },
+      "local-metadata",
+    ),
+    {
+      isLocal: false,
+      url: "wss://remote-sfu.example.org",
+      room: {
+        serverInfo: { region: "remote", version: "4.5.6" },
+        metadata: "remote-metadata",
+        engine: { client: { ws: { url: "wss://remote-sfu.example.org" } } },
+      } as unknown as LivekitRoom,
+    },
+  ];
+
   it("renders and matches snapshot", async () => {
     const client = createMockMatrixClient();
 
-    const livekitRooms: {
-      room: LivekitRoom;
-      url: string;
-      isLocal?: boolean;
-    }[] = [
-      createMockLivekitRoom(
-        "wss://local-sfu.example.org",
-        { region: "local", version: "1.2.3" },
-        "local-metadata",
-      ),
-      {
-        isLocal: false,
-        url: "wss://remote-sfu.example.org",
-        room: {
-          serverInfo: { region: "remote", version: "4.5.6" },
-          metadata: "remote-metadata",
-          engine: { client: { ws: { url: "wss://remote-sfu.example.org" } } },
-        } as unknown as LivekitRoom,
-      },
-    ];
-
     const { container } = render(
       <DeveloperSettingsTab
         client={client}
@@ -93,4 +105,140 @@ describe("DeveloperSettingsTab", () => {
 
     expect(container).toMatchSnapshot();
   });
+  describe("custom livekit url", () => {
+    afterEach(() => {
+      customLivekitUrlSetting.setValue(null);
+    });
+    const client = {
+      doesServerSupportUnstableFeature: vi.fn().mockResolvedValue(true),
+      getCrypto: () => ({ getVersion: (): string => "x" }),
+      getUserId: () => "@u:hs",
+      getDeviceId: () => "DEVICE",
+    } as unknown as MatrixClient;
+    it("will not update custom livekit url without roomId", async () => {
+      const user = userEvent.setup();
+
+      render(
+        <TooltipProvider>
+          <DeveloperSettingsTab
+            client={client}
+            env={{} as unknown as ImportMetaEnv}
+          />
+        </TooltipProvider>,
+      );
+
+      const input = screen.getByLabelText("Custom Livekit-url");
+      await user.clear(input);
+      await user.type(input, "wss://example.livekit.invalid");
+
+      const saveButton = screen.getByRole("button", { name: "Save" });
+      await user.click(saveButton);
+      expect(getSFUConfigWithOpenID).not.toHaveBeenCalled();
+
+      expect(customLivekitUrlSetting.getValue()).toBe(null);
+    });
+    it("will not update custom livekit url without text in input", async () => {
+      const user = userEvent.setup();
+
+      render(
+        <TooltipProvider>
+          <DeveloperSettingsTab
+            client={client}
+            roomId="#testRoom"
+            env={{} as unknown as ImportMetaEnv}
+          />
+        </TooltipProvider>,
+      );
+
+      const input = screen.getByLabelText("Custom Livekit-url");
+      await user.clear(input);
+
+      const saveButton = screen.getByRole("button", { name: "Save" });
+      await user.click(saveButton);
+      expect(getSFUConfigWithOpenID).not.toHaveBeenCalled();
+
+      expect(customLivekitUrlSetting.getValue()).toBe(null);
+    });
+    it("will not update custom livekit url when pressing cancel", async () => {
+      const user = userEvent.setup();
+
+      render(
+        <TooltipProvider>
+          <DeveloperSettingsTab
+            client={client}
+            roomId="#testRoom"
+            env={{} as unknown as ImportMetaEnv}
+          />
+        </TooltipProvider>,
+      );
+
+      const input = screen.getByLabelText("Custom Livekit-url");
+      await user.clear(input);
+      await user.type(input, "wss://example.livekit.invalid");
+
+      const cancelButton = screen.getByRole("button", {
+        name: "Reset overwrite",
+      });
+      await user.click(cancelButton);
+      expect(getSFUConfigWithOpenID).not.toHaveBeenCalled();
+
+      expect(customLivekitUrlSetting.getValue()).toBe(null);
+    });
+    it("will update custom livekit url", async () => {
+      const user = userEvent.setup();
+
+      render(
+        <TooltipProvider>
+          <DeveloperSettingsTab
+            client={client}
+            roomId="#testRoom"
+            env={{} as unknown as ImportMetaEnv}
+          />
+        </TooltipProvider>,
+      );
+
+      const input = screen.getByLabelText("Custom Livekit-url");
+      await user.clear(input);
+      await user.type(input, "wss://example.livekit.valid");
+
+      const saveButton = screen.getByRole("button", { name: "Save" });
+      await user.click(saveButton);
+      expect(getSFUConfigWithOpenID).toHaveBeenCalledWith(
+        expect.anything(),
+        "wss://example.livekit.valid",
+        "#testRoom",
+      );
+
+      expect(customLivekitUrlSetting.getValue()).toBe(
+        "wss://example.livekit.valid",
+      );
+    });
+    it("will show error on invalid url", async () => {
+      const user = userEvent.setup();
+
+      render(
+        <TooltipProvider>
+          <DeveloperSettingsTab
+            client={client}
+            roomId="#testRoom"
+            env={{} as unknown as ImportMetaEnv}
+          />
+        </TooltipProvider>,
+      );
+
+      const input = screen.getByLabelText("Custom Livekit-url");
+      await user.clear(input);
+      await user.type(input, "wss://example.livekit.valid");
+
+      const saveButton = screen.getByRole("button", { name: "Save" });
+      (getSFUConfigWithOpenID as Mock).mockImplementation(() => {
+        throw new Error("Invalid URL");
+      });
+      await user.click(saveButton);
+      expect(
+        screen.getByText("invalid URL (did not update)"),
+      ).toBeInTheDocument();
+      expect(customLivekitUrlSetting.getValue()).toBe(null);
+    });
+  });
 });