Form protection with simple captcha calculations.

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

Merb plugin that provides resource access rate limits and captcha'ing

A honeypot style captcha extension for ActiveRecord. Simple one-line inclusion in the model combined with a simple form field should trap the bad guys in the molasses.

This gem enable to use Captchme. Anti spam, Monetize captcha and Audience qualification

Block repetetive requests from logged_in users and shows captcha.

you will get arithmatic sum with answer you just have to compare with ur user in controller

Ruby wrapper for Yandex.Cleanweb

Russian Post tracking toolset, consisting tracking form bot (since Russian Post is too retarded for normal API) and captcha solver/recognizer.

This is a gem wrapper for tiny captcha in C with no dependencies.

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

A gem to generate captcha pictures.

Display and verify arcaptcha service captcha

Antispam helps prevent spam in your Rails applications by checking against DNS blacklists and spam-prevention databases. It has two core features: (1) IP-based spam detection using Project Honey Pot to block known spammers automatically, and (2) content-based spam detection using Defendium’s mach...

This gem provides integration with TrustCaptcha for Ruby applications, offering CAPTCHA verification with a focus on security and privacy.