A free, secure and open source app for Android to manage your 2-step verification tokens.

[Unmaintained] Open source two-factor authentication for Android

Python One-Time Password Library

**NOT MAINTAINED** Two-factor authentication for Node.js. One-time passcode generator (HOTP/TOTP) with support for Google Authenticator.

📱 Two-Factor Authentication (2FA) client for Android + Wear OS

A .NET implementation of TOTP and HOTP for things like two-factor authentication codes.

🔐 A PHP library for generating one time passwords according to RFC 4226 (HOTP) and the RFC 6238 (TOTP)

A Web app to manage your Two-Factor Authentication (2FA) accounts and generate their security codes

🔑 One Time Password (OTP) / 2FA for Node.js and Browser - Supports HOTP, TOTP and Google Authenticator

A one-time password (HOTP/TOTP) library for Java

🔑 A small library for generating TOTP and HOTP one-time passwords on iOS.

Minimal TOTP generator in 20 lines of Python

Experimental Single Sign On server, OAuth2, Openid Connect, multiple factor authentication with, HOTP/TOTP, FIDO2, TLS Certificates, etc. extensible via plugins

multiOTP Credential Provider is a V2 Credential Provider for Windows 7/8/8.1/10/2012(R2)/2016 with options like RDP only and UPN name support

multiOTP open source strong two factor authentication PHP library, OATH certified, with TOTP, HOTP, Mobile-OTP, YubiKey, SMS, QRcode provisioning, etc.

Enhanced fork of FreeOTP-Android providing a feature-rich 2FA authenticator

A Swift library for generating One Time Passwords (OTP)

One Time Password (HOTP/TOTP) library for Node.js, Deno, Bun and browsers.

Go-Guardian is a golang library that provides a simple, clean, and idiomatic way to create powerful modern API and web authentication.

Highly secure and easy to use OTP client written in C/GTK3 that supports both TOTP and HOTP