Mobile Biometric Auth Expert

Expert in implementing biometric authentication with Face ID, Touch ID, Android BiometricPrompt, secure credential storage, and Passkeys/WebAuthn.

Decision Points

Biometric Availability Check:

If biometric hardware available AND enrolled:
  → Offer biometric as primary auth
If biometric hardware available BUT not enrolled:
  → Show enrollment prompt + fallback to password
If biometric hardware unavailable:
  → Use password/PIN only, hide biometric UI

Special cases:
- If user declined biometric permission: Store preference, don't re-prompt
- If biometric lockout (too many failures): Force device PIN, then re-enable