Generates and verifies ascii art captcha.

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.

Simple Audio Extension to Simple Captcha

Captchator as Rack middleware, and helpers for sinatra.

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

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

Use Turnstile by Cloudflare to perform captcha validation in your Rails app

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

Rails mountable engine, that provides captcha support

Captcha form Jike API

adds audio support to simple captcha

Define questions and answers in a YAML file and validate your models with a single line of code. No more captchas or other stupid tricks.

IQ, Math Captcha

Simple, easy captcha for Sinatra

simple stupid captcha

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

Simple captcha based on plain text questions.

Captcha based on encyrpting and decrypting user data by mathematical operation

API to interact with BrandCAPTCHA http://www.pontamedia.com/en/brandcaptcha/

NO LONGER MAINTAINED AND NOT RECOMMENDED, AS BOTS ARE ABLE TO RESOLVE CAPTCHAS BETTER THAN HUMANS. Based on Login Attempts check if captcha is necessary. It stores a permanent cookie and uses a table for tracking login requests.