Imported from andrewyng/context-hub (content/flutter/skills/state-management/riverpod/SKILL.md). Install upstream with npx skills add andrewyng/context-hub --skill riverpod. Copyright stays with the author.

Flutter Riverpod State Management

Use this skill when building Flutter state management with riverpod and flutter_riverpod.

Core Rule

• Use Provider for read-only values and dependency wiring.
• Use StateProvider for small mutable state.
• Use FutureProvider for one-shot async loading.
• Use StreamProvider for reactive streams.
• Use Notifier or AsyncNotifier for feature state that needs mutation methods.
• Use autoDispose for short-lived state.
• Use family when provider output depends on an argument.
• Use flutter_riverpod in Flutter apps.
• If you use flutter_riverpod, you usually do not add riverpod separately because the Flutter package brings it in transitively.
• Current stable line is Riverpod 3.x (riverpod 3.2.1, flutter_riverpod 3.3.1).

Decision Guide

Choose Riverpod when:

• you want provider-based dependency injection and reactive state in one model
• state should be derived from other providers
• async data is a major part of the feature
• test overrides and scoped state matter
• you want fewer classes than a Bloc-heavy approach

Choose a different pattern when:

• the feature is a tiny local state toggle and a simple widget would be enough
• the logic is better expressed as an explicit event machine

Required Project Setup

For Dart-only code:

• add riverpod

For Flutter UI code:

• add flutter_riverpod
• wrap the app in ProviderScope
• use ConsumerWidget, Consumer, or ConsumerStatefulWidget where ref is needed

If code generation is used:

• add riverpod_annotation
• add riverpod_generator
• add build_runner

Implementation Pattern

Prefer this structure:

• providers own state, dependencies, and derived values
• repositories and APIs stay outside widgets
• UI reads state with ref.watch
• UI performs imperative reads with ref.read
• container-level overrides are used for tests, demos, and environment-specific wiring

Keep providers small and composable. Keep state immutable unless the provider type is specifically meant for mutation. Keep feature logic in providers or notifiers, not in widgets.

Lifecycle Rules

• Use autoDispose for short-lived screens and transient queries.
• Use ref.keepAlive() only when you want cached state to survive temporarily.
• Prefer provider disposal over manual cleanup.
• In tests and pure Dart code, dispose ProviderContainer when finished.

UI Binding Rules

Use ConsumerWidget when the whole widget depends on providers. Use Consumer when only a small subtree needs access to ref. Use ConsumerStatefulWidget when you need widget lifecycle plus ref. Use select to reduce rebuilds. Use ProviderListener or ref.listen for side effects.

Testing Rules

• Test providers through ProviderContainer.
• Override dependencies instead of mocking provider internals.
• Assert AsyncValue states directly for async providers.
• Dispose containers in tests.

Common Pitfalls

• Do not call ref.watch inside callbacks; use ref.read there.
• Do not skip ProviderScope at the app root.
• Do not use StateProvider for large feature state.
• Do not put business logic in widgets.
• Do not rebuild the whole tree when a single field changes; use select.
• Do not model async loading manually when FutureProvider or AsyncNotifier fits.
• Do not forget provider overrides for tests and previews.

What To Prefer In Answers

When writing code or advising on design:

• show the smallest working provider first
• mention whether ProviderScope is required
• mention whether the provider should be autoDispose or cached
• mention whether a family is needed for arguments
• include test override notes when dependencies are external
• keep examples aligned with the current Riverpod docs and Flutter integration patterns
• if code generation is involved, prefer matching riverpod_annotation / riverpod_generator versions from the same 3.x release line

Minimal Reference Checklist

• ProviderScope = app root setup
• ref.watch = rebuild on change
• ref.read = imperative access
• select = narrower rebuilds
• autoDispose = short-lived state
• family = parameterized provider
• ProviderContainer = test/headless container