I have finished watching a series of lessons on Designing and Versioning HTTP/REST APIs from well-known author Jeffrey Richter, who is an author of the best-sellers CLR via C# and Windows API via C++.
For those who design back-end APIs, I do definitely recommend watching it (and reading the books as well, if you haven't), especially those who think that doing an API is simple (probably, impressed by several "Hello, World!" prototypes made during the weekends).