Riverpod 2 Complete Guide: Notifiers, AsyncValue and Code Generation

Riverpod 2 with code generation is the state management approach most new Flutter projects reach for in 2026. It's compile-safe, testable, and decoupled from the widget tree. Here's the modern workflow.

A Generated Provider

part 'counter.g.dart';

@riverpod
class Counter extends _$Counter {
  @override
  int build() => 0;

  void increment() => state++;
}

Async Data With AsyncValue

AsyncNotifier models loading, data, and error as a single value you pattern-match in the UI — no manual flags:

@riverpod
Future<List<User>> users(UsersRef ref) async {
  final res = await http.get(Uri.parse('/api/users'));
  return parseUsers(res.body);
}

// In the widget
ref.watch(usersProvider).when(
  data: (users) => UserList(users),
  loading: () => const Spinner(),
  error: (e, _) => ErrorView(e),
);

Why Code Generation

• No more choosing the right provider type by hand — the generator infers it.
• Provider arguments become type-safe function parameters.
• Refactors are caught at compile time, not in production.