WordPress is, step by step, becoming an application framework, which implies the need for APIs that will allow new functionality. The REST API plugin is the physical manifestation through which the REST API will be used, its functionality being described in brief would be the retrieval of users, posts, taxonomies and other server-side data that by the means of this plugin will be achieved more easily. WP API will provide a simple and standard interface to the WP Query, the APIs of posts, users and post meta, which also includes an alternative API based on Backbone models that provides developers of WordPress themes and plugins with the possibility to get up and running, and retrieve data without knowing any details about how to connect to the said server.
This chapter will give you a crash course in WordPress REST API itself. Yes, the API itself. There is not much coding here, but if you need thorough background info about REST API in WordPress, this...