FreeOTP

Operating systems: Android, iOS

This open-source authenticator app was created after Google closed its Authenticator source code. The FreeOTP interface is ultraminimalistic, with nothing superfluous. This minimalist approach is especially apparent in the iOS version, which lacks even the option to create a token based on a secret key, leaving only QR-code scanning. The Android version retains both options, and it offers a lot of flexibility in manual token creation, letting users choose the type of generation (TOTP or HOTP), the number of characters in the code, the algorithm, and the refresh interval for the codes.

One disadvantage is that no version of the app supports cloud sync or token export and import in the form of a file, so once you start using the app, you’re stuck with it. In addition, in FreeOTP, you can’t set a PIN or protect app access any other way (in the iOS version, you can protect individual tokens with Touch ID or Face ID). The app hides codes by default, though, and also hides them automatically after 30 seconds of inactivity. FreeOTP’s final advantage is that it takes up minimal storage space, about 2MB–3МB (by comparison, Google Authenticator requires 15MB–20MB, and Microsoft Authenticator takes up 150MB–200MB).

Pros:

• No need for an account,
• Simple interface,
• Hidden codes as default,
• Codes automatically hidden after 30 seconds of inactivity,
• Minimal storage requirement,
• Touch ID or Face ID protection for tokens (iOS version only),
• Ability to search by token name (iOS version).

Cons:

• Inability to generate a token with a secret key (iOS version; requires scanning a QR code),
• Inability to export and import tokens,
• Inability to backup/sync,
• Lack of access protection.

Summary
Like all open-source apps, FreeOTP is a little quirky, but we cut it a lot of slack because its interface and overall storage requirements are so light.