When Drupal 8.0 was released two and a half years ago, with a built-in REST API, it signaled the start of Drupal's evolution to an API-first platform. Since then, each of the five new releases of Drupal 8 introduced significant web service API improvements. Drupal 8.6, shipping in September, will also have a new bunch of API improvements.
Recently Dries Buytaert, founder and project lead of Drupal (and co-founder, Chief Technology Officer, and Chairman of the Board of Acquia), published an update on Drupal's continuing evolution towards an API-first platform. Definitely worth a read.
At no point in the history of digital content has there ever been such a dizzying proliferation of devices in our lives, and experiences we encounter and consume.