reCAPTCHA4net (nuget): 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.
Keywords: reCAPTCHA|CAPTCHA|ASP.NET|MVC