Open Authenticator

Open Authenticator is a free, open-source TOTP (Time-based One-Time Password) manager built with Flutter. It works across Android, iOS, Windows, macOS, and Linux, giving you a consistent 2FA experience regardless of your platform.

Unlike Google Authenticator which locks you into a single device, Open Authenticator supports optional synchronization across devices through a backend that you can self-host. Your OTP secrets are stored securely on-device, and the app supports QR code scanning, otpauth:// link handling, and local biometric authentication.

The project emphasizes freedom and interoperability — you are never locked into one ecosystem, and you can always migrate your data. With multi-language support and community translations, Open Authenticator makes two-factor authentication accessible to users worldwide.