Simple captcha based on plain text questions.

Captcha form Jike API

A simple image captcha gem

Simple, easy captcha for Sinatra

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

generate captcha by dalli,use the memcache

HumanDetector is a friendly logic captcha for Rails the doesn't require any external system dependency (e.g. external captcha API connections). It uses a simple question that any 7 or more years old human can understand, but that a spambot will not be able to answer. This Gem supports Ruby v1.9.2 and Rails 3.0.x.

MVC based Math, Logic Captcha

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

A simple CAPTCHA implementation for Rails 5+ based on RMagick.

Captcha Client for YunPian.com

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

simple stupid captcha

adds audio support to simple captcha

Rails mountable engine, that provides captcha support

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

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

DeathByCaptcha allows you to solve captchas with manual labor

Rack middleware Captcha verification using Recaptcha API.

BrainBuster - a logic captcha for Rails