diff --git a/packages/data-connect/src/api/DataConnect.ts b/packages/data-connect/src/api/DataConnect.ts
index 9393b9ef4e4..27ab83660fd 100644
--- a/packages/data-connect/src/api/DataConnect.ts
+++ b/packages/data-connect/src/api/DataConnect.ts
@@ -160,6 +160,7 @@ export class DataConnect {
     this._transport = new this._transportClass(
       this.dataConnectOptions,
       this.app.options.apiKey,
+      this.app.options.appId,
       this._authTokenProvider,
       this._appCheckTokenProvider,
       undefined,
diff --git a/packages/data-connect/src/network/fetch.ts b/packages/data-connect/src/network/fetch.ts
index fbd930977ab..928b9f873cf 100644
--- a/packages/data-connect/src/network/fetch.ts
+++ b/packages/data-connect/src/network/fetch.ts
@@ -34,6 +34,7 @@ export function dcFetch<T, U>(
   url: string,
   body: U,
   { signal }: AbortController,
+  appId: string | null,
   accessToken: string | null,
   appCheckToken: string | null,
   _isUsingGen: boolean
@@ -48,6 +49,9 @@ export function dcFetch<T, U>(
   if (accessToken) {
     headers['X-Firebase-Auth-Token'] = accessToken;
   }
+  if (appId) {
+    headers['x-firebase-gmpid'] = appId;
+  }
   if (appCheckToken) {
     headers['X-Firebase-AppCheck'] = appCheckToken;
   }
diff --git a/packages/data-connect/src/network/transport/index.ts b/packages/data-connect/src/network/transport/index.ts
index 8ccbc88f435..5518faa0f95 100644
--- a/packages/data-connect/src/network/transport/index.ts
+++ b/packages/data-connect/src/network/transport/index.ts
@@ -45,6 +45,7 @@ export interface CancellableOperation<T> extends PromiseLike<{ data: T }> {
 export type TransportClass = new (
   options: DataConnectOptions,
   apiKey?: string,
+  appId?: string,
   authProvider?: AuthTokenProvider,
   appCheckProvider?: AppCheckTokenProvider,
   transportOptions?: TransportOptions,
diff --git a/packages/data-connect/src/network/transport/rest.ts b/packages/data-connect/src/network/transport/rest.ts
index aaaf22abd64..85847868c5d 100644
--- a/packages/data-connect/src/network/transport/rest.ts
+++ b/packages/data-connect/src/network/transport/rest.ts
@@ -39,6 +39,7 @@ export class RESTTransport implements DataConnectTransport {
   constructor(
     options: DataConnectOptions,
     private apiKey?: string | undefined,
+    private appId?: string,
     private authProvider?: AuthTokenProvider | undefined,
     private appCheckProvider?: AppCheckTokenProvider | undefined,
     transportOptions?: TransportOptions | undefined,
@@ -175,6 +176,7 @@ export class RESTTransport implements DataConnectTransport {
           variables: body
         } as unknown as U, // TODO(mtewani): This is a patch, fix this.
         abortController,
+        this.appId,
         this._accessToken,
         this._appCheckToken,
         this._isUsingGen
@@ -203,6 +205,7 @@ export class RESTTransport implements DataConnectTransport {
           variables: body
         } as unknown as U,
         abortController,
+        this.appId,
         this._accessToken,
         this._appCheckToken,
         this._isUsingGen
diff --git a/packages/data-connect/test/emulatorSeeder.ts b/packages/data-connect/test/emulatorSeeder.ts
index df7071a5868..36cdf691169 100644
--- a/packages/data-connect/test/emulatorSeeder.ts
+++ b/packages/data-connect/test/emulatorSeeder.ts
@@ -82,7 +82,6 @@ export async function setupQueries(
     connection_string:
       'postgresql://postgres:secretpassword@localhost:5432/postgres?sslmode=disable'
   };
-  fs.writeFileSync('./emulator.json', JSON.stringify(toWrite));
   return fetch(`http://localhost:${EMULATOR_PORT}/setupSchema`, {
     method: 'POST',
     body: JSON.stringify(toWrite)
diff --git a/packages/data-connect/test/unit/fetch.test.ts b/packages/data-connect/test/unit/fetch.test.ts
index f0d7f38ee8c..a50ac188724 100644
--- a/packages/data-connect/test/unit/fetch.test.ts
+++ b/packages/data-connect/test/unit/fetch.test.ts
@@ -40,7 +40,15 @@ describe('fetch', () => {
       message
     });
     await expect(
-      dcFetch('http://localhost', {}, {} as AbortController, null, null, false)
+      dcFetch(
+        'http://localhost',
+        {},
+        {} as AbortController,
+        null,
+        null,
+        null,
+        false
+      )
     ).to.eventually.be.rejectedWith(message);
   });
   it('should throw a stringified message when the server responds with an error without a message property in the body', async () => {
@@ -51,7 +59,15 @@ describe('fetch', () => {
     };
     mockFetch(json);
     await expect(
-      dcFetch('http://localhost', {}, {} as AbortController, null, null, false)
+      dcFetch(
+        'http://localhost',
+        {},
+        {} as AbortController,
+        null,
+        null,
+        null,
+        false
+      )
     ).to.eventually.be.rejectedWith(JSON.stringify(json));
   });
 });
diff --git a/packages/data-connect/test/unit/gmpid.test.ts b/packages/data-connect/test/unit/gmpid.test.ts
new file mode 100644
index 00000000000..c6679ca242d
--- /dev/null
+++ b/packages/data-connect/test/unit/gmpid.test.ts
@@ -0,0 +1,84 @@
+/**
+ * @license
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { deleteApp, initializeApp, FirebaseApp } from '@firebase/app';
+import { expect, use } from 'chai';
+import * as sinon from 'sinon';
+import sinonChai from 'sinon-chai';
+
+import { DataConnect, executeQuery, getDataConnect, queryRef } from '../../src';
+import { initializeFetch } from '../../src/network/fetch';
+
+use(sinonChai);
+const json = {
+  message: 'unauthorized'
+};
+const fakeFetchImpl = sinon.stub().returns(
+  Promise.resolve({
+    json: () => {
+      return Promise.resolve(json);
+    },
+    status: 401
+  } as Response)
+);
+
+describe('GMPID Tests', () => {
+  let dc: DataConnect;
+  let app: FirebaseApp;
+  const APPID = 'MYAPPID';
+  beforeEach(() => {
+    initializeFetch(fakeFetchImpl);
+    app = initializeApp({ projectId: 'p', appId: APPID }, 'fdsasdf'); // TODO(mtewani): Replace with util function
+    dc = getDataConnect(app, { connector: 'c', location: 'l', service: 's' });
+  });
+  afterEach(async () => {
+    await dc._delete();
+    await deleteApp(app);
+  });
+  it('should send a request with the corresponding gmpid if using the app id is specified', async () => {
+    // @ts-ignore
+    await executeQuery(queryRef(dc, '')).catch(() => {});
+    expect(fakeFetchImpl).to.be.calledWithMatch(
+      'https://firebasedataconnect.googleapis.com/v1alpha/projects/p/locations/l/services/s/connectors/c:executeQuery',
+      {
+        headers: {
+          ['x-firebase-gmpid']: APPID
+        }
+      }
+    );
+  });
+  it('should send a request with no gmpid if using the app id is not specified', async () => {
+    const app2 = initializeApp({ projectId: 'p' }, 'def'); // TODO(mtewani): Replace with util function
+    const dc2 = getDataConnect(app2, {
+      connector: 'c',
+      location: 'l',
+      service: 's'
+    });
+    // @ts-ignore
+    await executeQuery(queryRef(dc2, '')).catch(() => {});
+    expect(fakeFetchImpl).to.be.calledWithMatch(
+      'https://firebasedataconnect.googleapis.com/v1alpha/projects/p/locations/l/services/s/connectors/c:executeQuery',
+      {
+        headers: {
+          ['x-firebase-gmpid']: APPID
+        }
+      }
+    );
+    await dc2._delete();
+    await deleteApp(app2);
+  });
+});
diff --git a/packages/data-connect/test/unit/queries.test.ts b/packages/data-connect/test/unit/queries.test.ts
index 444601bd5ea..68bd96268a6 100644
--- a/packages/data-connect/test/unit/queries.test.ts
+++ b/packages/data-connect/test/unit/queries.test.ts
@@ -68,7 +68,7 @@ describe('Queries', () => {
   it('[QUERY] should retry auth whenever the fetcher returns with unauthorized', async () => {
     initializeFetch(fakeFetchImpl);
     const authProvider = new FakeAuthProvider();
-    const rt = new RESTTransport(options, undefined, authProvider);
+    const rt = new RESTTransport(options, undefined, undefined, authProvider);
     await expect(rt.invokeQuery('test', null)).to.eventually.be.rejectedWith(
       json.message
     );
@@ -77,7 +77,7 @@ describe('Queries', () => {
   it('[MUTATION] should retry auth whenever the fetcher returns with unauthorized', async () => {
     initializeFetch(fakeFetchImpl);
     const authProvider = new FakeAuthProvider();
-    const rt = new RESTTransport(options, undefined, authProvider);
+    const rt = new RESTTransport(options, undefined, undefined, authProvider);
     await expect(rt.invokeMutation('test', null)).to.eventually.be.rejectedWith(
       json.message
     );
@@ -86,7 +86,7 @@ describe('Queries', () => {
   it("should not retry auth whenever the fetcher returns with unauthorized and the token doesn't change", async () => {
     initializeFetch(fakeFetchImpl);
     const authProvider = new FakeAuthProvider();
-    const rt = new RESTTransport(options, undefined, authProvider);
+    const rt = new RESTTransport(options, undefined, undefined, authProvider);
     rt._setLastToken('initial token');
     await expect(
       rt.invokeQuery('test', null) as Promise<unknown>