A library to make creating negative captchas less painful

A plugin to make the process of creating a negative captcha in Rails much less painful

Drop in feedback engine with customizable fields, and captcha available

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

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

Google reCaptcha helpers and verifier

DeathByCaptcha allows you to solve captchas with manual labor

TwoCaptcha allows you to solve captchas with manual labor

Unobtrusive, flexible and simple spam protection for Rails applications using honeypot strategy for better user experience.

adds audio support to simple captcha

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

SimpleCaptcha is available to be used with Rails 3 + 4 or above and also it provides the backward compatibility with previous versions of Rails.

Anti Captcha is an automated CAPTCHA solving service

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.

Captcha-Plugin for Rails

RubyGem package for visualCaptcha's backend service

Rack middleware Captcha verification using Recaptcha API.

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.

A simple way to add honeypot captchas to Rails forms

BrainBuster - a logic captcha for Rails