SimpleCaptcha is available to be used with Rails 3 or above and also it provides the backward compatibility with previous versions of Rails.

This plugin adds helpers for the YinXiangMa CAPTCHA API

A very simple rack captcha middleware via captchator.com API

anti-captcha is a Ruby library for recognize captcha on anti-captcha.com

This is mt first gem

Forked from https://github.com/kares/simple_captcha

RedisCaptcha provides simple captcha that can be read by human.

Anti-spam protection for your website

Wrapper for Captchabot.com

SimpleCaptcha is available to be used with Rails 3 or above and also it provides the backward compatibility with previous versions of Rails.

Ruby package for easy integration with the API of 2captcha captcha solving service to bypass recaptcha, hcaptcha, funcaptcha, geetest and solve any other captchas.

Merb plugin that provides resource access rate limits and captcha'ing

A simple image captcha gem

Rack middleware Captcha verification using Recaptcha API.

ZeroCaptcha allows companies to solve captchas with artificial intelligence software, which is faster than humans and very accurate

Captcha based on encyrpting and decrypting user data by mathematical operation

Simple negative captcha for Rails

Description of RailsCaptcha.

This version include two important page 'Contact' and 'Register' with the 'Math-Captcha' method submit for prevent hacker attack.

Ruby port of VIT AutoCaptcha