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.

The idi_captcha_generator gem provides a customizable CAPTCHA solution tailored for high-traffic applications, ensuring that only legitimate users can access features like sign-up and login forms. By leveraging image-based questions, it prevents automated systems from bypassing security measures....

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.

A captcha solver (only for easy ones) gem

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

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

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

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

A Google-style captcha for enterprise Rails apps

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

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

Gem that uses RuCaptcha API to solver any type of captcha

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...

generate captcha by dalli,use the memcache

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

Death by Captcha Ruby implementation (HTTP API)