Web APIs are not just useful when making headless sites in Drupal: large Drupal sites often hold valuable information that could also be useful outside the site's context. Media companies might want to expose historical media content, community sites could show data about their community activities, e-commerce sites tend to open an API for their affiliates and partners.

While it is possible to use Drupal 7 and Drupal 8 as an API backend, a lot of functionalities that describe a mature API service do not come out of the box. In this post we will explain what key concepts you have to keep in mind when designing an API service, why they are important and how APIgee Edge can make it easier to build a full-featured API webservice in Drupal successfully.