Mobile Authentication

Use the project brief to find the provider SDK/configuration, session owner, credential store, redirect handlers and account-scoped repositories. Preserve the chosen provider and the requested audit/implementation scope. Read installed versions and the provider's actual backend contract before selecting APIs.

Pick the reference

Project	Read
Flutter	references/flutter.md
Android	references/android.md
iOS	references/ios.md
React Native / Expo	references/react-native.md
Kotlin Multiplatform	references/kotlin-multiplatform.md

Define identity and session transitions

• Separate provider identity, backend account, session credentials and local unlock. Biometric approval alone is not server authentication.
• Model restoring, signed out, authenticating, signed in, reauthentication required and signing out as needed by the real flow. Temporary offline restoration is distinct from proven invalid credentials.
• Give each attempt a correlation identifier and cancellation owner. A cancelled sign-in or reauthentication preserves any existing valid session; it cannot silently replace it with a partially authenticated account.
• Complete account switching by invalidating old jobs, caches and notification bindings before exposing the new account's data. Fence late callbacks with account/session generation.

Choose the provider-supported ceremony

• For OAuth/OIDC native login, use a maintained provider/library implementation of Authorization Code with PKCE through the system authentication browser. Keep client secrets off the app; verify redirect association and response binding using the SDK's documented protections.
• For passkeys, the backend issues challenges and verifies registration/authentication responses, relying-party identity and replay protections. Native credential APIs alone do not prove identity to your backend. Define recovery for unavailable credentials without weakening authentication.
• Link providers only after proving control according to the provider contract; matching email strings is not sufficient authority to merge accounts. Define collisions, cancellation and recovery before altering account ownership.
• Treat sensitive actions as backend-authorized operations with the required fresh authentication. Do not bypass reauthentication by changing a UI flag.

Refresh, logout and recovery

• Use the provider SDK's session management if it already owns refresh. Otherwise coalesce refresh work per session; every waiter receives success, cancellation or failure, and retries have a bound.
• Before saving a refresh result, check that the session is still current. Logout/account switch must make an old result inert, including its queued request replays.
• Apply the provider's supported refresh-token protection. OAuth security guidance supports rotation or sender-constrained refresh tokens for public clients; do not invent a rotation endpoint or override SDK behavior.
• On logout, invalidate local access and clear scoped state. Track remote revocation separately when supported; if offline, report that it was not confirmed and use the provider's documented recovery strategy. Browser SSO logout and app logout are different operations.
• Recovery, MFA and linking error messages follow the actual identity provider and product requirements. Avoid exposing whether another account exists through custom recovery behavior.

Verify and deliver

Test cancelled login, malformed/replayed callback, process recreation during login, concurrent refresh, offline restoration, logout during refresh, account switching, unavailable passkey, linking collision and cancelled reauthentication. Exercise provider integration in its test environment; keep tokens and personal data out of fixtures/logs.

Return a transition table tied to real symbols, provider/backend boundaries, storage and redirect changes, test results and remaining configuration evidence. Use mobile-security for threat review and secure storage, mobile-firebase for Firebase Auth APIs, and mobile-privacy for deletion.

Official sources

• OAuth for native apps, RFC 8252
• OAuth security best current practice, RFC 9700
• Android Credential Manager
• Apple AuthenticationServices