Axelerant was entrusted with the task of developing a Drupal 8 based partial headless backend and had to come to a mutually acceptable format for the REST-based API endpoints in the backend. After careful consideration, the OpenAPI 3.0 specification was selected as the format for describing the APIs.
Axelerant launched Legacy.com, a top 50 U.S. website, on a headless Drupal platform. An incredible Node, React, RESTful, and Drupal implementation.
The RESTful module (7.x-1.x version) has a multitude of caching options. This will help you get started with Drupal RESTful caching.