If you want two-factor authentication without handing your secrets to a third-party cloud, these five open-source apps keep secrets encrypted locally and leave sync entirely up to you. Aegis leads on Android, FreeOTP is the most minimal, 2FAS is the best iOS option, KeePass suits desktop power users, and 2FAuth is for self-hosters.
Most popular 2FA apps — Google Authenticator, Microsoft Authenticator, Authy — quietly phone home or force you into a cloud account. That's convenient, but it means your one-time codes (and the seeds that generate them) sit on someone else's server, behind their security and their terms of service.
If that bothers you, there's a better path. A handful of open-source authenticators store your TOTP secrets in an encrypted vault on your own device, never auto-sync to a vendor cloud, and let you decide if, when, and how backups happen. That's the trade-off: you give up automatic cross-device sync and take on responsibility for your own backups, but you gain full control over your secrets.
Here are five apps that fit that philosophy, ranked by how well they balance privacy, usability, and platform coverage.
Aegis is the strongest choice for Android users who want a no-cloud 2FA app. It's fully open-source and stores all your TOTP and HOTP entries in an AES-256 encrypted vault that lives on your device1. There's no account to create, no telemetry, and no cloud sync — backups are encrypted files you export and store wherever you choose1.
The vault is protected by a password or biometric unlock, and the app supports importing from Google Authenticator, Authy, and other apps if you're migrating. It's Android-only, which is the main limitation, but on that platform it's hard to beat for the privacy-first crowd.
Why it's the top pick: Encrypted local vault, user-controlled backups, open-source, zero cloud dependency. It hits every requirement of the no-cloud-sync angle without compromise.
FreeOTP is Red Hat's open-source authenticator, and it's about as barebones as it gets2. No account, no sync, no cloud, no backup mechanism — just a clean app that generates codes. That maximalist approach to minimalism means maximum transparency: there's simply nothing to phone home.
The downside is also obvious: if you lose your phone, you lose your secrets unless you've manually re-registered them elsewhere. For users who see that as a feature rather than a bug, FreeOTP is the purest option on this list2.
Why it's here: Absolute zero-network-footprint 2FA. No backup also means no attack surface.
2FAS is the most polished cross-platform option. It's open-source, runs on both iOS and Android, and offers optional iCloud or Google Drive backups that you can simply leave disabled for a fully offline experience3. A browser extension lets you push codes to your desktop without typing, which is a genuine convenience feature that doesn't require any cloud account to function3.
For iPhone users specifically, 2FAS is the best fit: it respects the no-cloud requirement (sync is opt-in and can be turned off entirely) while offering a smoother experience than FreeOTP and broader platform support than Aegis3.
Why it's here: The only pick that gives iOS users a polished, open-source, no-cloud-capable authenticator with extras like the browser extension.
KeePass isn't a dedicated 2FA app — it's an offline password manager with TOTP support via plugins. Its encrypted database (.kdbx) lives on your local storage, and you can use KeePassXC on desktop or KeePassDX on Android to manage both passwords and one-time codes in a single offline vault4. No subscription, no cloud, full user control4.
This is the pick for people who already use (or are willing to learn) KeePass and want to consolidate credentials and 2FA into one encrypted file they control completely. The learning curve is steeper, and TOTP setup requires a plugin, but the payoff is a single offline database for everything.
Why it's here: Unifies passwords and 2FA in one offline encrypted database — ideal for desktop-centric power users who want zero cloud and don't mind configuration.
2FAuth flips the "no cloud" concept: instead of avoiding cloud entirely, you run your own. It's a web-based authenticator you deploy via Docker on your own server, supporting TOTP and HOTP with data encryption5. Since the server is yours, any "cloud" involved is infrastructure you control — no third party ever sees your secrets.
This is the pick for people who already self-host services (perhaps behind a VPN or reverse proxy) and want browser-based access to their 2FA codes from any device without trusting a vendor. It's more involved than a mobile app, but it's the most flexible option for users comfortable with Docker and server administration5.
Why it's here: Web-based access without third-party clouds. The "cloud" is yours.
If privacy and no cloud sync are your priorities, steer clear of:
These apps are fine for convenience, but they don't meet the bar for this list.
| If you want… | Pick |
|---|---|
| The best Android-only encrypted vault | Aegis |
| The absolute simplest, zero-feature app | FreeOTP |
| A polished iOS experience with optional extras | 2FAS |
| Passwords and 2FA in one offline database | KeePass |
| Web access from your own server | 2FAuth |
All five are open-source and auditable. The right choice comes down to your platform and how much setup you're willing to do.
AskBuy may earn a commission when you click through to some of the apps listed above. That doesn't influence our recommendations — these picks are based on the privacy and no-cloud criteria described here.
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