wxianfeng_simple_captcha is captcha for rails,modified from simple_captcha .

Anti Captcha is an automated CAPTCHA solving service

anti-captcha is a Ruby library for recognize captcha on anti-captcha.com

Simple gem to add captcha or negative captcha to your Rails 3 application

Tencent Cloud Ruby SDK is the official software development kit, which allows Ruby developers to write software that makes use of Tencent Cloud service CAPTCHA.

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

A captcha solver (only for easy ones) gem

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

A captcha verification approach for Rails apps, directly integrated into ActiveRecord’s validation mechanism and providing helpers for ActionController and ActionView.

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.

A Google-style captcha for enterprise Rails apps

A Google-style captcha for enterprise Rails apps

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...

Gem that uses RuCaptcha API to solver any type of captcha

A simple and custom captcha for Rails3.

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

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.

Captcha form Jike API

Simple, easy captcha for Sinatra

Captcha Client for YunPian.com