ReCaptcha implements view helpers to generate ReCaptcha code, with the noscript counterpart, required methods that interface with the HTTP API for captcha verification, a DSL to generate a before_filter and the code to implement AJAX captcha validation.

RMagickCaptcha is a gem that implements captcha for using in Rails application.

Simple reverse captcha solution that consist in create a hidden field that should be always empty.

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

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

DeathByCaptcha allows you to solve captchas with manual labor

Rack middleware Captcha verification using Recaptcha API.

BrainBuster - a logic captcha for Rails

Rails extension for Cloudflare's Turnstile CAPTCHA alternative. This gem should work with Rails 6.x, 7.x, 8.x and with Faraday 1.x and 2.x.

ActsAsTextcaptcha provides spam protection for Rails models with text-based logic question captchas. Questions are fetched from Rob Tuley's textcaptcha.com They can be solved easily by humans but are tough for robots to crack.

Despamilator is a plugin based spam detector designed for use on your web forms borne out of two annoyances: Spam being submitted in my web forms and CAPTCHAS being intrusive. Despamilator will apply some commonly used heuristics from the world of anti-spam to help you decide whether your users a...

Arithmetic Captcha

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FerrumMCP is a browser automation server that implements the Model Context Protocol (MCP), enabling AI assistants to interact with web pages through a standardized interface. Features include navigation, form interaction, content extraction, screenshot capture, JavaScript execution, cookie manage...

Drop in feedback engine with customizable fields, and captcha available

ALTCHA is a free, open-source CAPTCHA alternative that protects your website from spam and abuse. This gem implements the ALTCHA v1 challenge protocol (challenge creation and submission verification) and integrates with Rails.cache for replay protection.

RubyGem package for visualCaptcha's backend service

Repackaged visualCaptcha's backend service, including translation and minor modification. Mainly for private use. Everything still belongs to original author: emotionLoop. ...

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

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.