Proton Authenticator

Proton Authenticator creates time-based one-time codes for people who want a dedicated authenticator on phones and computers. It is a strong fit for users who value offline access, open-source software, and optional encrypted sync without an account requirement. Its wide import support makes switching practical, but it is not the choice for users who require a hardware security key.

Overview

The app generates TOTP codes on your device, and those codes remain available when you are offline. You can use it without a Proton Account; signing in is optional and enables cross-device syncing. That separation suits someone who wants a standalone authenticator on one device, while users who need synchronized codes must opt into an account.

Proton Authenticator is open source, so its code can be inspected. Vault unlocking also supports face or fingerprint recognition, adding a biometric gate to access without changing how the account codes themselves work.

Key features

Moving and protecting codes

Imports are supported from Google Authenticator, 2FAS, Aegis Authenticator, Bitwarden Authenticator, Ente Auth, and LastPass Authenticator. That makes it easier to move an existing collection from several established apps. Proton Authenticator also exports codes, which gives users an exit route if their needs change.

You can back up codes locally or in the cloud. When sync is enabled, entries are protected with 256-bit AES-GCM and end-to-end encryption; Proton says its servers cannot access the unencrypted data. This provides a way to keep codes in step across devices while limiting server access, though sync is optional rather than required for offline use.

Pricing

Proton Authenticator is free on all platforms. The Free plan costs nothing and has no ads or tracking; the Proton Authenticator plan is also free, with no ads or tracking and availability on all platforms. There is no paid tier or free trial to weigh against the free option, so the practical choice is whether to use optional syncing, not which subscription to buy.

Platforms

Apps are available for Android, iOS, Windows, macOS, and Linux, with the Android app also offered through F-Droid. The broad desktop and mobile coverage is useful for people who want an authenticator beyond a phone alone.

Who it's for

Choose Proton Authenticator if you want free TOTP codes, offline access, optional encrypted synchronization, and a way to import from another popular authenticator. It also suits users who prefer open-source software or biometric vault unlocking. Look elsewhere if storing credentials on a YubiKey is central to your setup, or if you need authentication features beyond the TOTP codes described here.

Pros and cons

• Pros: Free across desktop and mobile, with no ads or tracking, means no subscription barrier across its supported platforms.
• Pros: Offline code display and optional syncing accommodate both single-device use and a multi-device setup.
• Pros: Local or cloud backup, broad import support, and export make migration and recovery more flexible.
• Cons: Using sync requires signing in to a Proton Account, so it is not account-free across devices.
• Cons: Codes are TOTP-based; users looking specifically for credentials stored and generated with a hardware key should consider another app.

Alternatives

Compare authenticator apps if you want to survey more options. Yubico Authenticator is the better fit if you want a free, open-source app that requires a YubiKey to store credentials and generate codes. Bitwarden is worth considering if you want an authenticator within a broader password-management product, with a free plan and a free trial.

Ente Auth is another free, open-source option with importing and exporting. SAASPASS Authenticator offers a free personal mobile app as well as a freemium product with a free trial. Zoho OneAuth is a free alternative for Zoho work accounts and personal online accounts.

Duo Mobile is an option for teams: its Duo Free plan covers 10 users, while Duo Essentials costs $3 a month. LastPass may suit someone seeking an authenticator alongside a password manager; its Free plan is limited to one device type. LoginTC is an alternative with a free Cloud Starter plan for up to 3 users.

Verdict

Proton Authenticator is an easy recommendation for anyone who wants a free TOTP app that works offline, spans phones and computers, and can sync or back up codes with encryption. Its imports, exports, and lack of ads or tracking make it particularly practical for switching and everyday use. Choose another option if you need hardware-key storage or a broader account-security service rather than a dedicated authenticator.