Use the final applicationId from android/app/build.gradle.kts when registering your Android app in Firebase. A registration for a different package name will not match your build.

Configure the application

1. Add or select the matching Android app in Firebase project settings.
2. Download its client configuration as google-services.json.
3. Place it at android/app/google-services.json.
4. Run FlutterFire configuration for the same Firebase project and Android app.
5. Check that lib/firebase_options.dart refers to that project.

The source already applies com.google.gms.google-services in the Android build configuration. Preserve that setup; do not add duplicate plugin declarations. See the Firebase Flutter setup guide.

Notification resources

The main manifest declares notification permission and references high_importance_channel and @drawable/notification_icon. The notification service uses these same resources. If rebranding, keep those references valid or update them together.

Rebuild and test

Perform a full rebuild after changing Firebase files. Sign in as a test customer and allow notifications when prompted. Send a message to that contact from the module’s push administration page.

If the build reports “No matching client found,” compare the built application ID with the package name inside your downloaded configuration. Do not manually replace identifiers inside an unrelated JSON file; obtain the correct file from Firebase.