Open Authenticator
Free, open-source cross-platform TOTP authenticator with self-hostable sync backend, built with Flutter.
Open source alternative to:
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.
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Frequently Asked Questions
Why should I switch from Google Authenticator to Open Authenticator?
Google Authenticator locks your 2FA codes to a single device, while Open Authenticator lets you synchronize your OTP secrets across devices through a backend you can self-host. It is free and open source under GPL-3.0, built with Flutter, and works consistently on Android, iOS, Windows, macOS, and Linux. You are never locked into one ecosystem, and your data can always be migrated.
How does Open Authenticator keep my 2FA secrets secure?
OTP secrets are stored securely on-device, with optional local biometric authentication to unlock the app. Synchronization is done through a backend that you run yourself, so your secrets are never stored on someone else's server. This on-device-first design with optional self-hosted sync is the key privacy advantage over hosted authenticator apps.
Which platforms and entry methods does Open Authenticator support?
Open Authenticator runs on Android, iOS, Windows, macOS, and Linux, all from a single Flutter codebase. It supports QR code scanning, otpauth:// link handling, and manual entry for adding accounts. The app also offers multi-language support through community translations.
Repository details
Updated 8/12/2026, 5:00:28 PM
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