Simple, easy captcha for Sinatra

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

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

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...

Captcha form Jike API

A simple image-based CAPTCHA engine for Rails 6+, works offline and supports Devise integration

Captcha Client for YunPian.com

Simple Audio Extension to Simple Captcha

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

Gem that uses RuCaptcha API to solver any type of captcha

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

MVC based Math, Logic Captcha

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

adds audio support to simple captcha

simple stupid 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.

A simple CAPTCHA system to block bots in Rails apps.

generate captcha by dalli,use the memcache

A simple image captcha gem