Transition Seamlessly from Email Login to Biometric Authentication
After a successful email/password login, the app should detect whether the device supports biometric authentication and prompt the user to enable it. If accepted, future logins bypass the email/password form and authenticate using the device biometric, with the stored credentials validated against the secure session. The email/password login remains available as a fallback. This two-step onboarding (email first, biometric after) was explicitly required by all three organisations in the workshop.
User Story
Acceptance Criteria
- Given a successful first email/password login on a biometric-capable device, When the user reaches the home screen, Then a prompt appears offering to enable Face ID or fingerprint login for future sessions
- Given the user accepts biometric setup, When they next open the app with a valid stored session, Then the biometric prompt is shown instead of the login form
- Given biometric authentication succeeds, When the session is resumed, Then the user is navigated to the home screen within 1 second
- Given biometric authentication fails (e.g. unrecognised face), When the system falls back, Then the email/password login form is presented with the message 'Biometric login failed. Please sign in with your email and password.'
- Given the device does not support biometrics, When the first login completes, Then no biometric prompt is shown and the flow continues normally
- Given the user declines biometric setup, When they reopen the app later, Then the email/password form is shown without any biometric prompt unless the user enables it in settings
Business Value
All three organisations explicitly requested biometric login as the day-to-day authentication method, with email/password used only at first login. Biometric authentication reduces the time to open the app from ~10 seconds (typing credentials) to under 1 second, which is transformative for field use. For HLF's peer mentor with 380 registrations per year, this difference compounds into significant time savings and dramatically lowers the barrier to consistent reporting.
Components
- Biometric Authentication Screen ui
- Biometric Authentication Service service
- Biometric Prompt Overlay ui
- Biometric Unavailable Banner ui
- Biometric Authentication Service service
- Session Resume Manager service
- Secure Session Storage data
- Local Auth Integration infrastructure
- Biometric Authentication Service service
Dependencies
- Sign In with Email and Password critical
- Remain Logged In Across App Restarts critical