2FAS: an authenticator you can audit
Open source, with backups, and rated 4.7 across 35,020 reviews. The code that holds your second factors is published and checkable.
The distinguishing feature is not a feature: the source code is published.
For an app that holds the second factor to every account you own, that is not an ideological point. Anyone can check that the codes go nowhere.
What that buys in practice
Backup exists and you can see how it works. With closed apps you take the developer's word for it.
35,020 ratings at 4.7 — a smaller crowd than Google's million, and about as satisfied.
Where it falls behind
Update pace. Releases come slower than from Google and Microsoft. For a TOTP generator this matters less than it sounds — the standard does not move — but it is worth watching.
83 MB for a list of six-digit codes. Not a problem, just not lean.
Common questions
- Is 2FA Authenticator (2FAS) available on Android?
- Yes, the app ships for both iPhone and Android. We last checked both stores on September 1, 2026.
- What languages does 2FA Authenticator (2FAS) support?
- Of the languages this site covers, the App Store lists: English, German, Spanish. The store page shows the full list for your region.
- Is 2FA Authenticator (2FAS) free?
- 2FA Authenticator (2FAS) is free outright: no subscription and no in-app purchases are listed in the App Store.