A library to make creating negative captchas less painful

Ruby wrapper for Yandex.Cleanweb

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

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

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

Google reCaptcha helpers and verifier

Gem that uses RuCaptcha API to solver any type of captcha

This library can help you create a captcha in your terminal application, which may be damaged by a large influx of requests.

Rails extension for Cloudflare's Turnstile CAPTCHA alternative. This gem should work with Rails 6.x and 7.x, and with Faraday 1.x and 2.x.

A simple way to add zero friction captchas to Rails forms

jQuery slide captcha system with jQuery & jQuery UI for Rails 3

Form protection with simple captcha calculations.

Easy to use classical captcha for Rails apps

Anti Captcha is an automated CAPTCHA solving service

A smart captcha library

A captcha solver (only for easy ones) gem

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

wxianfeng_simple_captcha is captcha for rails,modified from simple_captcha .

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