A Google-style captcha for enterprise Rails apps

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

generate captcha by dalli,use the memcache

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

Implements view helpers for the ASIRRA CAPTCHA system for Rails-based websites

Submit captcha images and retrieve the text as a string.

Captcha form Jike API

A simple and fast image captcha generator that uses opencv and memcached.

Simple captcha

A simple way to add zero friction captchas to Rails forms

This is a Captcha gem for ruby. It drawing captcha image with C code so it no dependencies.

Simple reverse captcha solution that consist in create a hidden field that should be always empty.

Block repetetive requests from logged_in users and shows captcha.

wxianfeng_simple_captcha is captcha for rails,modified from simple_captcha .

SimpleCaptcha is the simplest and a robust captcha. Its implementation requires adding up a single line in views and in controllers/models. SimpleCaptcha is available to be used with Rails2.0 or above and also it provides the backward compatibility with previous versions of Rails.

Display and verify arcaptcha service captcha

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

Anti-spam protection for your website

Simple Audio Extension to Simple Captcha

Arithmetic Captcha