Simple Audio Extension to Simple Captcha

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

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

adds audio support to simple captcha

Death by Captcha Ruby implementation (HTTP API)

Captcha Client for YunPian.com

A Ruby library for integrating Private Captcha verification into your applications

EU captcha protects your website/API against abuse like form spam and credential stuffing

Simple captcha based on plain text questions.

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

simple stupid captcha

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...

generate captcha by dalli,use the memcache

MVC based Math, Logic Captcha

Captcha form Jike API

Simple, easy captcha for Sinatra

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

Gem that uses RuCaptcha API to solver any type of captcha

A simple CAPTCHA system to block bots in Rails apps.

RedisCaptcha provides simple captcha that can be read by human.