Connect your app

Fireemu serves the same protocols and default ports as the Local Emulator Suite, so you connect to it the same way.

Server code and the Admin SDK

The Firebase Admin SDK and the Google Cloud client libraries read the emulator environment variables. fireemu exec sets them for the command it runs:

npx fireemu exec -- node ./scripts/seed.mjs

Variable	Value
FIRESTORE_EMULATOR_HOST	Firestore host:port
FIREBASE_AUTH_EMULATOR_HOST	Authentication host:port
FIREBASE_STORAGE_EMULATOR_HOST, STORAGE_EMULATOR_HOST	Storage host:port and http://host:port
GCLOUD_PROJECT, GOOGLE_CLOUD_PROJECT	The project ID
FIREEMU_CONTROL_URL, FIREEMU_CONTROL_TOKEN	Fireemu’s control API, used by fireemu/testing

Variables for the other emulators (Realtime Database, Pub/Sub, Eventarc, Cloud Tasks, App Check, the Hub) are listed with the conditions in Environment variables. Variables for emulators that are not selected are left as your environment had them.

import { initializeApp } from 'firebase-admin/app';
import { getFirestore } from 'firebase-admin/firestore';

// Under `fireemu exec`, the Admin SDK finds the emulators from the environment.
initializeApp({ projectId: process.env.GCLOUD_PROJECT });
await getFirestore().doc('notes/n1').set({ text: 'hello' });

Client SDKs

Client SDKs are connected in code, as with the Local Emulator Suite. Use the project ID Fireemu runs with: the .firebaserc default, else daemon.authProject in fireemu.toml, else demo-app.

import { initializeApp } from 'firebase/app';
import { getAuth, connectAuthEmulator } from 'firebase/auth';
import { getFirestore, connectFirestoreEmulator } from 'firebase/firestore';
import { getStorage, connectStorageEmulator } from 'firebase/storage';
import { getFunctions, connectFunctionsEmulator } from 'firebase/functions';

const app = initializeApp({
  projectId: 'demo-app',
  apiKey: 'fake-api-key',
  storageBucket: 'demo-app.appspot.com',
});

connectAuthEmulator(getAuth(app), 'http://127.0.0.1:9099');
connectFirestoreEmulator(getFirestore(app), '127.0.0.1', 8080);
connectStorageEmulator(getStorage(app), '127.0.0.1', 9199);
connectFunctionsEmulator(getFunctions(app), '127.0.0.1', 5001);

The default ports are listed in Install and run. The Realtime Database client needs its own databaseURL; see Realtime Database. Hosting is plain HTTP and needs no SDK setup (Firebase Hosting).

Security Rules unit tests

@firebase/rules-unit-testing works with Fireemu. Its unsigned mock ID tokens (authenticatedContext()) are accepted by default, also under the strict profile, and the routes it calls to load Firestore and Storage rules and to clear Firestore (testEnv.clearFirestore()) are served. So is withFunctionTriggersDisabled: the Hub accepts PUT /functions/disableBackgroundTriggers and enableBackgroundTriggers without a token from a client that sends no browser metadata (Origin, Sec-Fetch-Site). See Security Rules.

The project ID

Fireemu takes the project ID from, in order:

1. --project (-P) on the command line, as an ID or a .firebaserc alias;
2. the default project of the .firebaserc next to the loaded firebase.json;
3. daemon.authProject in fireemu.toml;
4. demo-app.