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

Ruby package for easy integration with the API of 2captcha captcha solving service to bypass recaptcha, hcaptcha, funcaptcha, geetest and solve any other captchas.

Rails mountable engine, that provides captcha support

Implementation of captcha (Completely Automated Public Turing-Test to Tell Computers and Humans Apart) that is both easy to use and easy to customize/extend.

Generates and verifies ascii art captcha.

Simple negative captcha for Rails

Death by Captcha Ruby implementation (HTTP API)

Implements view helpers for the ASIRRA CAPTCHA system for Rails-based websites

Integrate the AreYouAHuman.com CAPTCHA alternative human verification into your Ruby/Rails application

Captcha based on encyrpting and decrypting user data by mathematical operation

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

Captcha based on encyrpting and decrypting user data by mathematical operation

Submit captcha images and retrieve the text as a string.

Captchator as Rack middleware, and helpers for sinatra.

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

Arithmetic Captcha

Captcha Gem for Rails, which generates captcha image by Rust.

A captcha solver (only for easy ones) gem

RedisCaptcha provides simple captcha that can be read by human.

Simple negative captcha for Rails