Programming JavaScript Applications

Chapter 8. Building RESTful APIs

What is an API? If you’re reading this book, you know that it’s an application programming interface, but in the context of a RESTful API, we’re specifically talking about an interface that allows users and applications to interact with your application over HTTP using REST architecture (REpresentational State Transfer).

For a very basic overview of REST architecture, see RESTful JSON Web Services. You’ll have a chance to explore it in-depth later in this chapter.

Why should you build an API? First of all, you’re going to need a way to connect the user interface to your backend resources, like a database, logging services, and maybe some gateways to third-party APIs. But there are good reasons to expose parts of that API to the public as well.

Think carefully about the some of the most successful apps out there: Facebook, Twitter, Google Maps, Amazon (yeah, it’s an app—lots of them, actually). I can keep going, but I’d fill the rest of the book with examples. What do all of these have in common?

They all offer public APIs that developers can use to enhance the value of the platform for its users. With a public API, your application is more than an app: it’s a platform that other developers will flock to and integrate their apps with. They’ll expose your app to new users and make your app more attractive to your existing users, because now it works with other tools that they already use.

But you don’t want just any API. You want a beautifully designed ...