Google Authenticator Android

Google Authenticator for Android is the open-source two-factor authentication app that generates time-based (TOTP) and counter-based (HOTP) one-time codes entirely on the device. It’s designed to be simple, offline, and standards-compliant, so any service that supports OATH OTP can interoperate with it. The app streamlines enrollment via QR codes or manual key entry, then displays rotating numeric codes with clear account labels to reduce mistakes during login. Because secrets are stored on the device and codes are computed locally, it works even without a data connection and avoids server-side dependencies. The UI focuses on clarity and safety cues—timers, account naming, and basic management—to make 2FA adoption accessible to non-experts. For developers, the project doubles as a reference implementation of OTP enrollment, storage, and code generation on Android.