Chapter 10. Testing APIs
According to Wikipedia, an API is defined as an "application programming interface". Well, it is a nice definition but it would be good to be more precise. In the context of web development, an API usually refers to a server-side API. The described interface is called over an HTTP protocol with a set of defined request/response messages that are usually in the XML or JSON format.
From the programming point of view, it doesn't matter which technology is behind the web service; communication is based on a set of standards.
Not so long ago, there existed very popular services based on Service Oriented Architecture (SOA) that used Simple Object Access Protocol (SOAP) messages together with Web Services Description Language