I'm implementing silent Firebase Anonymous Login alongside Supabase Auth, per FlutterFlow's own documented recommendation (Push Notifications docs: "consider implementing Anonymous Firebase Login" for users who need FCM tokens registered even while logged out of Supabase).
Setup:
- Authentication Type: Supabase (Push Notifications toggle is OFF, since it's incompatible with Supabase Auth)
- Custom Pub Dependencies: firebase_auth 5.3.3, firebase_core 3.6.0, firebase_messaging 15.2.7, mobile_scanner 5.2.3
I added a Custom Action that calls Firebase.initializeApp() (if not already initialized) then FirebaseAuth.instance.signInAnonymously(). On a real Android device, fresh release-signed APK install, this fails every time with:
PlatformException(channel-error, Unable to establish connection on channel., null, null)
Anonymous sign-in is enabled in Firebase Console (Authentication > Sign-in method). SHA-1 fingerprint is registered and matches my upload keystore. No new Firebase user ever appears in the console after this runs.
My question: is there a known-good version pairing for firebase_auth + firebase_core that works with FlutterFlow's current build pipeline for this pattern, or a required build/cache step I'm missing?