Authentication for Your First Mobile App: A Vibe-Coding Checklist
Avoid common login and session mistakes when using AI coding agents to add authentication to a mobile app.
Define the session lifecycle
Decide what happens on app start, after a successful login, after logout, when a token expires, and when the network is unavailable. Ask the agent to document the state transitions before writing the screens.
Protect data at the backend
The client should never be the only place that checks ownership. Database policies or server-side authorization must enforce which records the current user can read and change. Test a request using the wrong user, not just the happy path.
Handle common states
Your first auth flow should cover:
- Invalid credentials
- Unverified email, if verification is required
- Expired sessions
- Slow or offline network
- Duplicate form submissions
- Password reset and account deletion expectations
Do not leak secrets
Keep service credentials, signing keys, and administrative tokens out of mobile code, prompts, screenshots, and Git history. Use environment configuration for public values and a trusted server for privileged operations.
Ask the agent for a security review
Codex, Claude Code, Cursor, and Copilot can all inspect an authentication implementation. Ask for a threat-focused review: “Find places where an unauthenticated or different user could access data. Explain the evidence and propose tests.”
Authentication is a foundation feature. Build it once using a consistent boilerplate pattern, then reuse it across every screen instead of inventing a new check in each component.