Before we dig in, let’s examine a use case that will help illustrate this approach through an example: the Petstore API. ACME produces, stores, and distributes pets to its beloved customers, and the whole process is managed in-house.
The increasing competition and the growing demand of the customer base are forcing ACME to rethink its distribution model. Namely, the distribution will be left to independent resellers that could sell pets locally, online or on-site. The main challenge is how to open up the information system so that independent resellers can discover the pets, check inventory, and so on. This can be done through the exposition of an API, of course.
Let’s help ACME to succeed in the API world!
Source: An API Journey: From Idea to Deployment the Agile Way–Part I, from Laurent Broudoux