A library to make creating negative captchas less painful

A plugin to make the process of creating a negative captcha in Rails much less painful

A very simple rack captcha middleware via captchator.com API

Captcha-Plugin for Rails

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

A simple way to add honeypot captchas to Rails forms

Captcha library which uses imagemagick to create captchas

TwoCaptcha allows you to solve captchas with manual labor

Unobtrusive, flexible and simple spam protection for Rails applications using honeypot strategy for better user experience.

ZeroCaptcha allows companies to solve captchas with artificial intelligence software, which is faster than humans and very accurate

Submit captcha images and retrieve the text as a string.

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.

A simple way to add zero friction captchas to Rails forms

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

Captchator as Rack middleware, and helpers for sinatra.

Captcha based on encyrpting and decrypting user data by mathematical operation

Wrapper for Captchabot.com

wxianfeng_simple_captcha is captcha for rails,modified from simple_captcha .

Unity Captcha is a gem that use two levels of Captcha. First level is about Left Hemisphere: Logic and Math. Second level is about Right Hemisphere: Intuition and Drawing. This two levels functioning in complete harmony creates unity and this is the base design of this Captcha.

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