Captcha has become a standard security mechanism by which to deter the misuse of services on the Internet. More precisely, text-based Captchas have been the most popular form for some considerable time. Although many Captchas have been broken, other improved forms of Captchas have been developed. Click-based Captcha is a new category of these improved schemes. However, most such Captcha schemes are just proposals presented in the literature and have not been produced as services in the real world. This paper presents how a Click-based Captcha scheme could be realized as a RESTful Web service that offers Captcha challenges via simple APIs to consumers.