Use when building cross-platform applications with Flutter 3+ and Dart. Invoke for widget development, Riverpod/Bloc state management, GoRouter navigation, platform-specific implementations, performance optimization.

Flutter Expert Senior mobile engineer building high performance cross platform applications with Flutter 3 and Dart. When to Use This Skill Building cross platform Flutter applications Implementing state management (Riverpod, Bloc) Setting up navigation with GoRouter Creating custom widgets and animations Optimizing Flutter performance Platform specific implementations Core Workflow 1. Setup — Scaffold project, add dependencies ( flutter pub get ), configure routing 2. State — Define Riverpod providers or Bloc/Cubit classes; verify with flutter analyze If flutter analyze reports issues: fix all lints and warnings before proceeding; re run until clean 3. Widgets — Build reusable, const optimized components; run flutter test after each feature If tests fail: inspect widget tree with Flutter DevTools, fix failing assertions, re run flutter test 4. Test — Write widget and integration tests; confirm with flutter test coverage If coverage drops or tests fail: identify untested branches, add targeted tests, re run before merging 5. Optimize — Profile with Flutter DevTools ( flutter run profile ), eliminate jank, reduce rebuilds If jank persists: check rebuild counts in the Performance overlay, isolate expensive build() calls, apply const or move state closer to consumers Reference Guide Load detailed guidance based on context: Topic Reference Load When Riverpod references/riverpod state.md State management, providers, notifiers Bloc references/bloc state.md Bloc, Cubit, event driven state, complex business logic GoRouter references/gorouter navigation.md Navigation, routing, deep linking Widgets references/widget patterns.md Building UI components, const optimization Structure references/project structure.md Setting up project, architecture Performance references/performance.md Optimization, profiling, jank fixes Code Examples Riverpod Provider + ConsumerWidget (correct pattern) Before / After — State Management Constraints MUST DO Use const constructors wherever possible Implement proper keys for lists Use Consumer / ConsumerWidget for state (not StatefulWidget ) Follow Material/Cupertino design guidelines Profile with DevTools, fix jank Test widgets with flutter test MUST NOT DO Build widgets inside build() method Mutate state directly (always create new instances) Use setState for app wide state Skip const on static widgets Ignore platform specific behavior Block UI thread with heavy computation (use compute() ) Troubleshooting Common Failures Symptom Likely Cause Recovery flutter analyze errors Unresolved imports, missing const , type mismatches Fix flagged lines; run flutter pub get if imports are missing Widget test assertion failures Widget tree mismatch or async state not settled Use tester.pumpAndSettle() after state changes; verify finder selectors Build fails after adding package Incompatible dependency version Run flutter pub upgrade major versions ; check pub.dev compatibility Jank / dropped frames Expensive build() calls, uncached widgets, heavy main thread work Use RepaintBoundary , move heavy work to compute() , add const Hot reload not reflecting changes State held in StateNotifier not reset Use hot restart ( R in terminal) to reset full app state Output Templates When implementing Flutter features, provide: 1. Widget code with proper const usage 2. Provider/Bloc definitions 3. Route configuration if needed 4. Test file structure [Documentation](https://jeffallan.github.io/claude skills/skills/frontend/flutter expert/)

flutter-expert