2FAS Auth is a free open-source authenticator app for people who want an extra step when signing in to online accounts.1 It works without a 2FAS account.1 It is a good choice if you want control over your sign-in codes and are willing to make a recovery plan.
Last checked October 28, 2026.
At a glance
- What it is: An app for TOTP and HOTP sign-in codes.2
- Works on: Android 9 or later;3 iPhone and iPad running iOS/iPadOS 18.6 or later, with an Apple Watch companion.4
- Price: Free.1
- Licence: GPL-3.0 for the Android code; app graphics have separate licensing terms.2
- Best for: People who want phone-based codes with a deliberate choice about backups.
- Official site: 2fas.com/auth
What 2FAS Auth does and how it protects your privacy
Think of an authenticator as a second key for your account. The Android project describes it as adding a one-time password from your phone alongside your username and password.2 Keep using strong, different passwords as well; the extra step complements that habit.
TOTP means a code that changes with time. HOTP means a code that advances with a counter. 2FAS supports services using either standard.2 Before switching, look in each account’s security settings for an authenticator option. Installing an app alone is not the same as enabling that option on your accounts.
According to its privacy policy, authentication data stays on your device rather than being transmitted to 2FAS servers.5 That makes the backup decision important: decide where another copy should live before trusting the app with essential accounts.
Key features of 2FAS Auth
- Offline codes: Generate codes without a live internet connection.1
- App locking: Protect access with a passcode or biometrics, such as a fingerprint.4
- Cloud synchronization: Use iCloud on iOS or Google Drive on Android.6
- Portable backups: Export a file and import it on another platform.6
- Password-protected recovery: Add your own password to a file or cloud backup.7
- Browser assistance: Confirm a browser code request in the mobile app instead of retyping it.1
2FAS Auth pros and cons
Pros
- A focused choice for keeping authentication separate from everyday password management.
- A useful fit for travel or other times when you prefer an offline routine.
- A choice of backup approaches, so you can plan recovery around your own circumstances.
- Published source code gives technically experienced people something concrete to inspect.
Cons
- Cloud sync stays within the same operating system; changing platforms calls for a file transfer.6
- The browser workflow requires confirmation on your phone.1
- The current Android series requires Android 9, which leaves out older devices.3
- A password-protected backup cannot help if you forget its password.7
Is 2FAS Auth safe and private?
The provider is Two Factor Authentication Service, Inc.5 The Android releases page lists version 6.1.0, released on October 19, as its latest release.3 The App Store lists iOS version 6.0.1.4 These recent updates support treating it as an actively maintained project. Only enter codes on the service you meant to visit, and decline unexpected browser requests.
The policy says 2FAS does not collect usage analytics, tracking IDs or advertising data.5 It does allow diagnostic processing, including Firebase Crashlytics reports, voluntarily submitted troubleshooting logs and extension installation information.5 Diagnostics are technical reports used to investigate faults. The policy says crash reporting can be disabled, and Firebase may receive technical data when crash reporting or push notifications are enabled.5
2FAS says communication between the phone and browser is end-to-end encrypted.1 This means the message is protected between those two endpoints. For backups, choose a strong, separate password and keep it somewhere you can reach without the lost phone. Do not assume that signing into a cloud account is the whole recovery plan.
In its response to a published security study, 2FAS acknowledged that older Android versions uploaded Google Drive backups before users added password protection.8 The company said it changed that process in late 2023 to prompt for a password before upload.8 That historical exchange is not a security certification for today’s app. Treat backup settings as a decision to make carefully, rather than a box to dismiss.
How to get started with 2FAS Auth
- Download the right app. Start at the official 2FAS Auth page and follow its download links. Choose Auth when you want sign-in codes.
- Start with one account. Open that service’s security settings and choose its authenticator setup. Keep the setup page open until you finish.
- Add the account. Follow the setup prompts to scan the displayed QR code or enter the supplied setup key. Treat that key as a secret; do not put a picture of it in a shared photo album.
- Confirm a sign-in. Enter the app’s code when the service requests it. Save the service’s recovery codes if it provides them, and test access before removing your old setup.
- Protect recovery. Set app protection, choose a backup method and add a backup password. Keep a separate copy somewhere safe, with the password stored separately.
- Practise before relying on it. Confirm that you can find your recovery material. Move other accounts gradually, keeping a checklist so nothing gets missed.
Who should use 2FAS Auth and who might prefer something else?
Choose 2FAS Auth if a phone is your preferred place for sign-in codes and you want to take ownership of recovery. It is especially appealing when a small, focused app feels easier to manage than another large account system. Spend your first few minutes on backups, not appearance settings.
If you would prefer a different routine for computer access or recovery, compare the Academy guides to Proton Authenticator and FreeOTP before choosing. If you are also organizing passwords, read about KeePassDX as a separate part of your account-security plan. Choose a routine you can recover from, as well as one you enjoy using.
Frequently asked questions about 2FAS Auth
Is 2FAS Auth free?
Yes, the official Auth page describes it as entirely free.1 Start with the authenticator’s own page when comparing costs; the same website also presents other products.
Does 2FAS Auth work on iPhone?
Yes, its App Store listing includes iPhone and iPad.4 Check your device against the current requirements in the box above before installing.
Can I move 2FAS Auth from Android to iPhone?
Yes, the official instructions describe exporting and importing a backup file across platforms.6 Make the transfer while you still have the old phone, and test the new one before erasing anything.
What should I prepare in case I lose my phone?
Keep a protected backup and the account recovery codes supplied by your services. Make sure your backup password and cloud recovery method are reachable without that phone. A recovery plan is most useful when you have practised finding everything before an emergency.
