The development of Web APIs has seen a surge in popularity in recent years. It is relatively easy to build Web APIs with Rails. You can generate JSON using Jbuilder or RABL. You can use 'respond_to' to share logic with a web application. You can also use another framework that specializes in Web APIs called Grape. However, there are some issues that come up after creating your API. Is your API sustainable? Does it break clients when you change your API? The versioning of APIs has drawn a lot of attention in blogs and podcasts such as Rebuild.fm. What does such versioning do for your API? The key to troubleshooting these problems and to creating a well-designed Web API is "Hypermedia". In this session, I will translate lessons from the book "RESTful Web APIs" (O'Reilly) to practical hints in building APIs using Rails, with a focus on hypermedia.