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StratumProton Authenticator
Free

Free and open source under the GPL 3.0 license.

 Free

Free and open source under the GPL, with no advertising. A Proton account is used for…

Android Windows, Linux, Android, iOS
  • Encrypted backups with import from other apps and export at any time
  • Supports TOTP, HOTP and mOTP
  • End-to-end encrypted sync between devices, which most free authenticators lack
  • Apps for Android, iOS, Windows, Linux and macOS
  • Android only, with no iOS or desktop version
  • Only handles one-time codes, not passwords
  • Sync requires a Proton account
  • Keeping codes on the same desktop you log in from weakens second-factor separation
Downloadable app Downloadable app
Open source Open source
License: GPL-3.0 License: GPL-3.0
No account needed No account needed
Works offline Works offline

Checked September 24, 2026

Checked September 21, 2026

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