diff --git a/scripts-available/CDB_FederatedServerDiagnostics.sql b/scripts-available/CDB_FederatedServerDiagnostics.sql
index 7b16263..2f727ea 100644
--- a/scripts-available/CDB_FederatedServerDiagnostics.sql
+++ b/scripts-available/CDB_FederatedServerDiagnostics.sql
@@ -1,12 +1,38 @@
+--------------------------------------------------------------------------------
+-- Private functions
+--------------------------------------------------------------------------------
+
+CREATE OR REPLACE FUNCTION @extschema@.__CDB_FS_Server_Diagnostics_PG(server_internal name)
+RETURNS jsonb
+AS $$
+BEGIN
+    RETURN '{}'::jsonb;
+END
+$$
+LANGUAGE PLPGSQL VOLATILE PARALLEL UNSAFE;
+
+
+
 --------------------------------------------------------------------------------
 -- Public functions
 --------------------------------------------------------------------------------
 
+--
+-- TODO: function documentation
+--
 CREATE OR REPLACE FUNCTION @extschema@.CDB_Federated_Server_Diagnostics(server TEXT)
-RETURNS json -- TODO decide if json or jsonb
+RETURNS jsonb
 AS $$
+DECLARE
+    server_internal name := @extschema@.__CDB_FS_Generate_Server_Name(input_name => server, check_existence => true);
+    server_type name := @extschema@.__CDB_FS_server_type(server_internal);
 BEGIN
-    RETURN '{}'::json;
+    CASE server_type
+    WHEN 'postgres_fdw' THEN
+        RETURN @extschema@.__CDB_FS_Server_Diagnostics_PG(server_internal);
+    ELSE
+        RAISE EXCEPTION 'Not implemented server type % for remote server %', server_type, server;
+    END CASE;
 END
 $$
 LANGUAGE PLPGSQL VOLATILE PARALLEL UNSAFE;
diff --git a/test/CDB_FederatedServerDiagnostics.sql b/test/CDB_FederatedServerDiagnostics.sql
index d0af580..0c1097e 100644
--- a/test/CDB_FederatedServerDiagnostics.sql
+++ b/test/CDB_FederatedServerDiagnostics.sql
@@ -1,2 +1,50 @@
+-- ===================================================================
+-- create FDW objects
+-- ===================================================================
+\set QUIET on
+SET client_min_messages TO error;
+\set VERBOSITY terse
+CREATE EXTENSION postgres_fdw;
+
+CREATE ROLE cdb_fs_tester LOGIN PASSWORD 'cdb_fs_passwd';
+GRANT CONNECT ON DATABASE contrib_regression TO cdb_fs_tester;
+
+-- Create database to be used as remote
+CREATE DATABASE cdb_fs_tester OWNER cdb_fs_tester;
+
+SELECT 'C1', cartodb.CDB_Federated_Server_Register_PG(server => 'loopback'::text, config => '{
+    "server": {
+        "host": "localhost",
+        "port": @@PGPORT@@
+    },
+    "credentials": {
+        "username": "cdb_fs_tester",
+        "password": "cdb_fs_passwd"
+    }
+}'::jsonb);
+\set QUIET off
+
+
+-- ===================================================================
+-- Test server diagnostics function(s)
+-- ===================================================================
 \echo '%% It raises an error if the server does not exist'
 SELECT '1.1', cartodb.CDB_Federated_Server_Diagnostics(server => 'doesNotExist');
+
+\echo '%% It returns a jsonb object'
+SELECT '1.2', pg_typeof(cartodb.CDB_Federated_Server_Diagnostics(server => 'loopback'));
+
+
+-- ===================================================================
+-- Cleanup
+-- ===================================================================
+\set QUIET on
+SELECT 'D1', cartodb.CDB_Federated_Server_Unregister(server => 'loopback'::text);
+DROP DATABASE cdb_fs_tester;
+
+-- Drop role
+REVOKE CONNECT ON DATABASE contrib_regression FROM cdb_fs_tester;
+DROP ROLE cdb_fs_tester;
+
+DROP EXTENSION postgres_fdw;
+\set QUIET off
diff --git a/test/CDB_FederatedServerDiagnostics_expect b/test/CDB_FederatedServerDiagnostics_expect
index ea8ac49..b8ffd9e 100644
--- a/test/CDB_FederatedServerDiagnostics_expect
+++ b/test/CDB_FederatedServerDiagnostics_expect
@@ -1,2 +1,6 @@
+C1|
 %% It raises an error if the server does not exist
-1.1|{}
+ERROR:  Server "doesNotExist" does not exist
+%% It returns a jsonb object
+1.2|jsonb
+D1|