This book’s primary focus is on designing hypermedia APIs. That may seem a bit strange to some readers. There are many books on programming languages, data storage systems, web frameworks, etc. This is not one of those books. Instead, this book covers the nature of the messages passed between client and server, and how to improve the content and value of those messages. I, personally, find this to be an exciting and fascinating area.

As of this writing anecdotal trends seem to indicate an ever-increasing reliance on APIs in web development. In general, this is a good thing. It means more and more developers are catching on to the notion that the World Wide Web is a great place to share not only data, but also services, a goal of those who championed the web in its early days.

However, I believe that this explosion of web APIs may lead us down a troublesome path. In my experience over the last few years, I have seen too many examples of implementations that rely on concepts of APIs rooted in desktop and local area network patterns that will not scale well at the WWW level, solutions still exhibiting brittleness that can lead to costly and frustrating maintenance issues as time goes by. In short, I don’t see enough hypermedia in API offerings for the web.

This book is an attempt to improve the chances that new APIs added to the WWW will be easier to use and maintain over time, and that they will take their cue from those who were responsible for the discovery of the value of hypermedia linking; the codification of the HTTP protocol; and the implementation of HTML, Atom/AtomPub, and other native hypermedia formats that still drive the growth of the web today.