A simple CAPTCHA system to block bots in Rails apps.

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

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

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

Simple Audio Extension to Simple Captcha

A simple image captcha gem

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...

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

generate captcha by dalli,use the memcache

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.

SimpleCaptcha is the simplest and a robust captcha. Its implementation requires adding up a single line in views and in controllers/models. SimpleCaptcha is available to be used with Rails2.0 or above and also it provides the backward compatibility with previous versions of Rails.

Death by Captcha Ruby implementation (HTTP API)

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

RedisCaptcha provides simple captcha that can be read by human.

Captcha Client for YunPian.com

A Ruby library for integrating Private Captcha verification into your applications

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

Captcha form Jike API

Simple captcha based on plain text questions.

adds audio support to simple captcha