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CAPTCHA was created at Carnegie Mellon University back in 2000. The most well known and widely used services are reCAPTcha and hCAPTCHA. These services have a client-side and server-side component for both services. Adding the client side bits for both is reasonably straightforward, but the server side of these is not always that simple. Free service [reCAPtCHAme] works with both services and can be implemented on any website.