Comparison

Fob vs 2FAS: An Honest Comparison

Published April 27, 2026. Recommends 2FAS over Fob in the cases where 2FAS is the right answer.

Most authenticator comparisons reduce to "ours is better, theirs is older." This one will not. 2FAS is one of the strongest TOTP apps shipping today, and a lot of the people reading this page do not need to leave it. The question is not which app is good. Both are. The question is which trade-offs match how you think.

The central trade-off is source code visibility versus closed source with a committed audit. 2FAS is FOSS under MPL-2.0. You can read the code, fork the repo, build it yourself if you want to. Fob is closed source. Trust comes from a third-party security audit committed post-launch, the export-always guarantee, and an architecture description you can verify by behavior. Both are defensible positions. They are not the same position.

The 60-second answer

Both apps export. Both apps run TOTP RFC 6238. Switching either direction is one file and a few minutes.

Side by side

The two rows that do most of the work are the first one and the last few. Source code visibility versus closed source with a committed audit is the headline trade. Cloud backup mechanism, shared-account model, and family sharing are where the architecture decisions diverge once you scale past one person on one platform.

Where 2FAS wins

This is the section that earns the rest of the page. 2FAS is good. Here is the specific shape of "good."

FOSS, MPL-2.0, publicly auditable. The 2FAS source is on GitHub under a permissive copyleft license. You can read it; if something is broken or backdoored, anyone with the time can find it and say so publicly. For users whose number-one requirement is "I can read the code if I want," 2FAS is the right answer in a way no closed-source product can match. Fob's published-audit model is a different posture, not a stronger one.

Browser extension with push-to-approve sign-ins. Most authenticators stop at "type the six digits into the box." 2FAS goes further: pair the phone app with the 2FAS browser extension, and a sign-in on a desktop becomes a phone notification you tap to approve. No code typing, no manual reading off a small screen. For users who sign in from a laptop frequently, this is a workflow win the rest of the market has not matched. Fob has no browser extension and no plans for one.

iOS today, fully featured, in production for years. 2FAS shipped on iOS early and has kept the app current. If you have an iPhone and you are deciding now, 2FAS works on your device today. Fob is Android-first and the iOS build follows; if you are on iOS and waiting is not an option, that decision is already made.

Free, no Premium tier, no upsell. 2FAS is genuinely free. There is no paid layer waiting to gate features you currently use, no subscription page, no "core is free, cloud backup is paid" split. Fob is free for the local-only experience but encrypted cloud backup is part of Fob Premium. If your principle is "I will never pay a subscription for a code generator," 2FAS respects that and Fob does not.

Cross-platform without phone-number identity. Authy required a phone number; Microsoft Authenticator nudges you toward a Microsoft account; 2FAS asks for neither. Fob shares this property for the local vault, but Fob's cloud backup does require a Fob account. If accountless is a hard requirement, 2FAS goes further than Fob does.

A documented, real encrypted export. The .2fas file is JSON with an AES-256-GCM ciphertext block and PBKDF2 key derivation, documented in the public repo. This is the export-always property that makes any authenticator safe to leave, and 2FAS gets it right.

Where Fob wins

Fob exists because there is a class of authenticator user that 2FAS does not serve well, even though the apps look superficially similar.

Multi-tag organization. This is Fob's load-bearing differentiator, and no major competitor including 2FAS has it. 2FAS gives you groups, one group per entry. A Coinbase account is crypto, exchange, or high-value, but only one of those at a time. Fob lets the same account carry all three simultaneously, and the filter UI is one tap. Past 60 accounts, single-axis grouping breaks down; this is the reason most 2FAS migrators we hear from migrated.

Family and shared accounts on the roadmap. Some accounts (the household streaming login, the shared bank login) belong to more than one person. 2FAS has no first-class model for this; sharing means handing over the device, rescanning a single-account QR, or splitting secret material between two installations. Fob's roadmap includes encrypted account sharing between Fob accounts, revocable from either side. If you have any account that two people legitimately use, this is the difference.

One single-vendor stack, one audit surface. 2FAS shipped is three pieces: the phone app, the browser extension, and the relay between them. Each adds attack surface to audit. Fob ships one app, with one architecture description and one audit cycle. For users who weight "fewest moving parts" highly, that is the cleaner shape.

Cloud backup that does not depend on iCloud or Google Drive. 2FAS backups are platform-specific: iCloud on iOS, Google Drive on Android. Restoring from an iPhone backup onto a Pixel is not a 2FAS feature; it is a manual file copy. Fob's end-to-end encrypted cloud backup is vendor-neutral, encrypted on-device with AES-256-GCM and Argon2id key derivation, and restores the same regardless of which platform you signed in from.

Architecture transparency through audits. Fob's first third-party audit is committed post-launch and will be posted at fob.codes/security in full when complete. The plan is to repeat it annually. This is not the same trust model as FOSS source visibility; it is a different model. For users who want a third-party security firm to look for what we missed and publish their findings, this is the substitute for source access.

When it depends

Three places the decision is genuinely mixed.

FOSS preference versus closed source with a committed audit. If reading the source is the property you care about most, 2FAS is the right answer. If reading an independent firm's audit report carries that weight, Fob is being built around that. Both are honest trust models; neither is objectively stronger.

Browser-extension dependency. 2FAS has it; Fob does not and will not. If push-to-approve from a desktop browser is the daily-use feature for you, that is a clear vote for 2FAS. If it is a "would be nice" rather than load-bearing, neither side gains or loses much.

iOS today versus roadmap. 2FAS ships iOS now. Fob will, but later. If your phone is iOS and you are deciding this week, 2FAS wins by default. If you are on Android, this row does not affect you.

The decision framework

Three questions pick the right app for you.

1. What is your trust model?
If you trust by reading source code, or trust someone who does, 2FAS is structurally a better fit. FOSS is its load-bearing feature. If you trust by reading audit reports and verifying behavior against a published architecture, Fob is being built around that posture. Both work; pick the one you actually do.

2. How much organization does your vault need?
Below 30 accounts, group-per-entry is fine and 2FAS handles it well. Above 30, multi-tag becomes a daily-use feature. Above 60, single-group filtering is actively painful and Fob is the clear fit.

3. Do you want one app, or an app plus extension?
2FAS's browser extension is genuinely useful. It is also additional surface to trust and additional pairing to maintain. Fob deliberately ships one phone app and nothing else. If "fewer moving parts" maps to your security model, Fob is closer. If "more workflow conveniences" maps to your daily use, 2FAS is closer.

If two of the three answers point to Fob, Fob is the move. If two point to 2FAS, stay on 2FAS. We are not trying to convert FOSS users who got to 2FAS for the right reasons; this page is for the population that hit the multi-tag or family-sharing wall and stayed because there was nowhere obvious to go.

Migration paths

If you are leaving 2FAS for Fob, the step-by-step is at /import/2fas. It takes about five minutes and uses the encrypted .2fas export.

If you are also comparing other apps, see /compare/fob-vs-google-authenticator for the Google Authenticator side and /compare/fob-vs-authy for Authy. The migration guides under /import/ cover Microsoft Authenticator, Aegis, Bitwarden, Duo, and Ente.

FAQ

Is Fob open source like 2FAS?

No. Fob is closed source. The trust substitutes are export-always (your vault leaves in an open format any time you ask), a published architecture at fob.codes/security, and a third-party security audit committed post-launch (posted in full when complete). If your top requirement is reading the code, those substitutes are not equivalent and 2FAS is the better pick. If your trust comes from committed-and-then-published audit reports and verifying export behavior, Fob is being built around that.

Does Fob have a browser extension?

No, and there are no plans for one. Fob is phone-first: codes live on your phone, you read them onto the desktop sign-in form. The 2FAS browser extension's push-to-approve flow is a real convenience, and if it is the feature keeping you on 2FAS, that is a fair reason to stay. Fob's design call is fewer moving parts: one app, one architecture, one audit cycle.

Can I keep both apps installed during migration?

Yes, and it is the recommended path. Use Fob as primary, leave 2FAS as fallback for a week, log into every account at least once with Fob codes, then uninstall 2FAS or wipe its vault. Exporting from 2FAS is non-destructive; the secrets stay on the original device until you remove them.

What to do next

If 2FAS fits your profile, stay on it. It is a strong app and the FOSS, browser-extension, and iOS-today properties are real wins that Fob does not match. We are not trying to convert anyone who got to 2FAS for those reasons.

If you want what Fob is building (multi-tag organization, family sharing on the roadmap, vendor-neutral end-to-end encrypted cloud backup, single-vendor stack with a committed audit), get it on Google Play. Android first; iOS comes after, and you can get notified from the homepage when the iOS build lands. The architecture is at fob.codes/security.

Questions this comparison did not answer? Email us at hello@fob.codes.