Trezur

TOTP (time-based one-time password) codes are derived from a time counter and refresh automatically, while HOTP (counter-based) codes advance from an incrementing counter. Trezur generates TOTP codes today, with HOTP support planned, so it is compatible with the majority of services that offer two-factor authentication. It works entirely in the browser and requires no account.

Trezur works entirely in the browser and keeps your data on your device, storing tokens encrypted at rest in browser storage with AES-256-GCM. You can optionally add a passcode for an extra layer of protection. It is a Progressive Web App, so you can install it for a native app-like experience and use most features offline.

Yes — Trezur supports importing and exporting your tokens, and you can set up automatic backups and multi-device sync with your preferred cloud service. Because it requires no account creation or cloud dependency, you stay in control of your authentication data. This makes it an open-source alternative to Google Authenticator and Microsoft Authenticator.