firebase-crashlytics

Firebase Crashlytics Skill

This skill defines how to correctly use Firebase Crashlytics in Flutter applications.

When to Use

Use this skill when:

• Implementing crash reporting in a Flutter project.
• Capturing fatal errors, non-fatal exceptions, and async/isolate errors.
• Customizing crash reports with keys, logs, and user identifiers.
• Configuring opt-in data collection or disabling reporting in debug builds.
• Uploading symbol files for obfuscated builds.

---

1. Setup and Configuration

flutter pub add firebase_crashlytics
flutter pub add firebase_analytics  # enables breadcrumb logs for better crash context

Run flutterfire configure to update the Firebase configuration and add the required Crashlytics Gradle plugin for Android.

import 'package:firebase_crashlytics/firebase_crashlytics.dart';

Obfuscated code:

• For apps built with --split-debug-info and/or --obfuscate, upload symbol files for readable stack traces.
• iOS: Flutter 3.12.0+ and Crashlytics Flutter plugin 3.3.4+ handle symbol upload automatically.
• Android: Use Firebase CLI (v11.9.0+) to upload Flutter debug symbols:

firebase crashlytics:symbols:upload --app=FIREBASE_APP_ID PATH/TO/symbols

---

2. Error Handling

Configure comprehensive error capture in main() to catch errors from all sources:

Fatal Flutter errors:

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();

  // Pass all uncaught fatal errors from the framework to Crashlytics
  FlutterError.onError = FirebaseCrashlytics.instance.recordFlutterFatalError;

  // Catch async errors not handled by the Flutter framework
  PlatformDispatcher.instance.onError = (error, stack) {
    FirebaseCrashlytics.instance.recordError(error, stack, fatal: true);
    return true;
  };

  runApp(MyApp());
}

Non-fatal Flutter errors: use recordFlutterError instead of recordFlutterFatalError.

Isolate errors:

Isolate.current.addErrorListener(RawReceivePort((pair) async {
  final List<dynamic> errorAndStacktrace = pair;
  await FirebaseCrashlytics.instance.recordError(
    errorAndStacktrace.first,
    errorAndStacktrace.last,
    fatal: true,
  );
}).sendPort);