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

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.

Captcha-Plugin for Rails

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

Arithmetic Captcha

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Quick little arithmetic plain-text captcha

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

Rack middleware Captcha verification using Recaptcha API.

DeathByCaptcha allows you to solve captchas with manual labor

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 are human or machine.

Captcha generator for rails

dongsx

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

Drop in feedback engine with customizable fields, and captcha available

这是一个验证码生成器。基于rucaptcha。本人只是将他的源码拉下来。为我的网站进行适配。因为我不使用sesion.id

A library to make creating negative captchas less painful

Ruby wrapper for Yandex.Cleanweb

TwoCaptcha allows you to solve captchas with manual labor

It's a Rails Captcha Engine for Rails 3 applications.