Implementation of captcha (Completely Automated Public Turing-Test to Tell Computers and Humans Apart) that is both easy to use and easy to customize/extend.

A Google-style captcha for enterprise Rails apps

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

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

Simple, easy captcha for Sinatra

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

A captcha verification approach for Rails apps, directly integrated into ActiveRecord’s validation mechanism and providing helpers for ActionController and ActionView.

Quick little arithmetic plain-text captcha

A Google-style captcha for enterprise Rails apps

Simple negative captcha for Rails

Despamilator is a plugin based spam detector designed for use on your web forms borne out of two annoyances: Spam being submitted in my web forms and CAPTCHAS being intrusive. Despamilator will apply some commonly used heuristics from the world of anti-spam to help you decide whether your users a...

A simple way to add honeypot captchas to Rails forms

ActsAsTextcaptcha provides spam protection for Rails models with text-based logic question captchas. Questions are fetched from Rob Tuley's textcaptcha.com They can be solved easily by humans but are tough for robots to crack.

Rack middleware Captcha verification using Recaptcha API.

reCAPTCHA was too much for us, so we created this. Simplest captcha ever.

Arithmetic 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.

Simple captcha based on plain text questions.

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

Captcha-Plugin for Rails