Securing Registration RESTful API against registering many users : <p>I am developing <code>RESTful APIs</code> with <code>ASP.NET WebAPI</code> for an <code>Android application</code> and there is an option to make a registration through our application. Suppose that our registration endpoint is something like '/api/register/' with some parameters like 'username', 'password' and 'email address'. So this endpoint is likely to be opened not only for Android device, but for everyone.</p>

<p>I mean it is easy to trace all the requests and responses to and from our server, so a bad person may calls this endpoint to start registering many users in our system.</p>

<p>I want to know how I can secure my API?</p>
