Thanks to the work of the WSCCI, Drupal 8 today provides a capable REST server out of the box that includes the ability to retrieve and modify content entities—such as nodes, users, taxonomy terms, and comments—through broadly understood create, read, update, and delete (CRUD) operations within HTTP requests.
The Web Services and Context Core Initiative
For Drupal to truly embrace the future web, we need to fundamentally rethink how Drupal responds to an incoming HTTP request. We need to treat HTML pages as what they are: A particularly common form of REST response, but only one among many. ...