A simple way to add zero friction captchas to Rails forms

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

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

A Rails captcha gem that attempts to determine whether or not a user is human.

Display and verify arcaptcha service captcha

To help with keep the bots at bay this gem helps you easily add honeypots to forms and/or obfuscate your form field names

A simple and custom captcha for Rails3.

Captcha Client for YunPian.com

Metabypass | Ruby-based easy implementation for solving any type of captcha by Metabypass

Generates Text Catpchas, that are 'nice' by my own personal definition!

Ruby wrapper for Yandex.Cleanweb

ALTCHA is a free, open-source CAPTCHA alternative that protects your website from spam and abuse

Due to many unrequited complaints to the recaptcha team with regard to its unreadability for real human users, this gem offers a more readable selection of captcha images.

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

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

Rails mountable engine, that provides captcha support

Antigate (Decode captcha service) wrapper for Ruby

A captcha that uses images instead of garbled text

simple stupid captcha

AntiCaptcha api ruby wrapper