RMagickCaptcha is a gem that implements captcha for using in Rails application.

Use Turnstile by Cloudflare to perform captcha validation in your Rails app

ReCaptcha implements view helpers to generate ReCaptcha code, with the noscript counterpart, required methods that interface with the HTTP API for captcha verification, a DSL to generate a before_filter and the code to implement AJAX captcha validation.

MVC based Math, Logic Captcha

My version of SimpleCaptcha

Simple gem to add captcha or negative captcha to your Rails 3 application

Simple lib to generate a math_captcha to prevent spammers in form. Supports localization.

Simple captcha

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

Description of TinyCaptcha.

Captchator as Rack middleware, and helpers for sinatra.

Block repetetive requests from logged_in users and shows captcha.

This gem enable to use Captchme. Anti spam, Monetize captcha and Audience qualification

Repackaged visualCaptcha's backend service, including translation and minor modification. Mainly for private use. Everything still belongs to original author: emotionLoop.

Rails mountable engine, that provides captcha support

API to interact with BrandCAPTCHA http://www.pontamedia.com/en/brandcaptcha/

Solve Media CAPTCHA Replacement

Simple captcha based on plain text questions.

Generates and verifies ascii art captcha.

simple stupid captcha