Today, in a strange turn of events, the term “REST” is mainly associated with JSON Data APIs, rather than with HTML and hypermedia. This is extremely funny once you realize that the vast majority of JSON Data APIs aren’t RESTful, in the original sense, and, in fact, can’t be RESTful, since they aren’t using a natural hypermedia format.
To re-emphasize: REST, as coined by Fielding, describes the pre-API web, and letting go of the current, common usage of the term REST to simply mean “a JSON API” is necessary to develop a proper understanding of the idea.