What is 2FA Fast?
2FA Fast is a free online two-factor authentication (2FA) code generator. It implements the TOTP standard (RFC 6238) entirely in your browser the same algorithm used by Google Authenticator, Microsoft Authenticator, and Authy. The underlying HMAC-based OTP algorithm is defined in RFC 4226.
We built it because sometimes you need your 2FA code and your phone is not available. Whether you are on a desktop, a borrowed computer, or just want a faster way to copy your code, 2FA Fast has you covered.
Why Cloud-Based Authenticators Are a Growing Risk
Google Authenticator and Microsoft Authenticator were originally designed as fully offline, device-local applications, meaning your 2FA secrets never left your phone. Both apps have since introduced cloud sync features that back up your authentication secrets to Google or Microsoft servers respectively.
While convenient, this creates a significant single point of failure: if your Google or Microsoft account is compromised, an attacker gains instant access to every 2FA secret tied to that account, including the codes protecting your banking, social media, and other critical services.
A compromised cloud account no longer just exposes your email. It can cascade into a full account takeover across your entire digital life. 2FA Fast takes the opposite approach: your secrets are processed exclusively in your browser and are never transmitted to, or stored on, any server.
Our Privacy Promise
Your 2FA secret key never leaves your browser. When you enter a secret key, all computation happens locally using the Web Crypto API a browser-native cryptography standard. No data is sent to our servers. Ever. You can verify this yourself by opening your browser's DevTools (F12), going to the Network tab, and generating a code. You will see zero outgoing requests carrying your secret.
The optional Save feature stores your account labels and secrets in your browser's localStorage, which lives entirely on your device and is not accessible to us or any third party.
Is It Safe?
Yes, with an important caveat: treat your 2FA secret key like a password. Anyone who has your secret key can generate valid codes. Only enter your secret key on trusted devices and connections. 2FA Fast uses HTTPS for all connections and our client-side code is open to inspection in your browser's DevTools.
For further reading on multi-factor authentication best practices, refer to the NIST SP 800-63B Digital Identity Guidelines and the OWASP Multifactor Authentication Cheat Sheet, both of which recommend TOTP as a secure second factor.
Suggest a Tool
We are actively building new tools and always looking for ideas. If there is a security or utility tool you would like to see added, reach out at contact@2fafast.com. We read every message.
