Top 20 NuGet captcha Packages

A library for using Google reCaptcha on server side.
EasyCaptcha library for Mvc
This is a client of Zamanak (www.zamanak.ir) web service
This is helper build of the BotDetect CAPTCHA nuget meant to be used ONLY with ASP.NET Core code running on top of legacy 4.5.1+ .NET frameworks. For the legacy ASP.NET code on legacy .NET, or for ASP.NET Core code on .NET Core frameworks you have to use our main CAPTCHA nuget. For the descriptio...
This is a google re-captcha for ASP.NET MVC web apps
Nice simple library for https://anti-captcha.com/ API.
Solve image captcha and recaptcha, easily using the imagetyperz-api library for C#
Fix RecaptchaOptions.ResponseValidationEndpoint This is a helper library for google reCAPTCHA 2.0 Getting started guide: https://github.com/PaulMiami/reCAPTCHA/wiki/Getting-started Change log: https://github.com/PaulMiami/reCAPTCHA/wiki/Change-log
Games library to distinguish human from machine input. (.NET Framework)
Easy to use Audio Captcha for Asp.net MVC Core
Library that implements the APIs of the most used captcha solving services.
The cure for comment spam. Subkismet is a comment spam filtering library that includes Akismet, Invisible Captcha, and Visible Captcha. The Akismet library included is based on code in use by Subtext and DasBlog.
FlexCaptcha is a freeware Captcha asp.net control that most significantly support either writing captcha images to disk or directly to http stream bypassing disk writing all toghether. In addition the captcha can reload and have many custom settings.
Honeypot anti bot mechanism implementation in ASP.NET MVC
reCAPTCHA4net allows to easily integrate Google reCAPTCHA (the most popular CAPTCHA service) into ASP.NET web application (both Web Forms or ASP.NET MVC are supported). It supports updated reCAPTCHA API, which provides the No CAPTCHA experience.
The ValidShapes is a .NET library used to integrate the ValidShapes CAPTCHA into the web applications based upon the asp.net platform. Try our CAPTCHA on http://www.validshapes.com/try-validshapes-captcha/ The ValidShapes CAPTCHA is free, responsive and handles touch events for mobile devices.
XCaptcha is an extendable and simple to use framework for creating CAPTCHA images.
This project contains the C# implemetation of the antigate API that can also be found at: http://l2-ip.com/antigate.net/downloads.html
Captcha generator class library