1. Treat session behavior as product behavior
A mobile session can expire while the app is in the background, while a form is open, while the network is unstable or after the backend has changed permissions. If this is not designed, every screen handles authentication differently.
The user should understand whether they are signed in, need to reauthenticate or lost access to a protected action.
- Define login, logout, token refresh and expired-session behavior early.
- Keep protected navigation aligned with authentication state.
- Avoid showing protected data after logout or account switch.
- Handle refresh failure with a clear path back to login.
- Document which API responses mean unauthenticated versus unauthorized.
2. Token storage must balance security and usability
Tokens are sensitive because they unlock API access. Mobile apps need a storage strategy that respects platform capabilities, app risk and user convenience. Storing tokens casually because it is easy can become a security and support problem later.
The storage decision should be paired with logging rules so tokens never appear in analytics, crash reports or support screenshots.
- Use secure storage for sensitive tokens when the risk requires it.
- Do not store secrets in plain configuration or logs.
- Clear session data when logout or account removal occurs.
- Avoid leaking authorization headers in error reporting.
- Review token lifetime with backend and business expectations.
3. Token refresh belongs in the API layer
If every screen knows how to refresh a token, the app becomes fragile. A central API client can coordinate refresh, retry safe requests and make failure behavior predictable.
The team still needs to decide which requests can be retried and how to avoid multiple simultaneous refresh attempts.
- Centralize authorized requests and refresh logic.
- Queue or coordinate requests while a refresh is in progress.
- Retry only when it is safe and intentional.
- Map refresh failure to a session-expired state.
- Record enough evidence to investigate repeated refresh problems.
4. Authentication needs support and security evidence
When users report that the app logged them out or denied access, support needs context: app version, account, route, API status, session event and whether permissions changed.
Good evidence reduces blame games between app, backend and infrastructure.
- Track session start, refresh failure and logout events safely.
- Include app version and API correlation when possible.
- Distinguish invalid credentials from expired session and missing role.
- Keep user-facing messages calm and specific.
- Review authentication incidents after release.
How to use this article
Treat this page as a decision aid. Use it with the related hub, checklist or service route when the topic affects production, customer experience, deployment, security or business continuity.