Firebase

Emulators Commands

Run Firebase services locally for development and testing. The emulator suite includes Firestore, Auth, Functions, Hosting, and Storage — test without touching production data.

5 commands

Pro Tips

Use 'firebase emulators:start --import=./seed --export-on-exit' to persist emulator data between sessions.

Access the emulator UI at http://localhost:4000 to visually inspect Firestore data, Auth users, and function logs.

Run 'firebase emulators:exec "npm test"' to start emulators, run tests, and auto-shutdown — perfect for CI.

Common Mistakes

Emulator data is lost on restart unless you use '--export-on-exit'. Always export if you need persistent test data.

Make sure your app connects to emulators in dev mode, not production Firebase. Check your initialization code.

Commands

Run script with emulators

$ firebase emulators:exec "npm test"

Start emulators, run script, then stop

Export emulator data

$ firebase emulators:export ./data

Export current emulator data to directory

Start with data import

$ firebase emulators:start --import=./data

Start emulators and import saved data

Start all emulators

$ firebase emulators:start

Start all configured Firebase emulators

Start specific emulators

$ firebase emulators:start --only functions,firestore

Start only specified emulators