HATEOAS is crucial to what [Roy Fielding](https://roy.gbiv.com/untangled/2008/rest-apis-must-be-hypertext-driven https://roy.gbiv.com/untangled/2008/rest-apis-m

HATEOAS is crucial to what [Roy Fielding](https://roy.gbiv.com/untangled/2008/rest-apis-must-be-hypertext-driven https://roy.gbiv.com/untangled/2008/rest-apis-must-be-hypert...) calls REST APIs. >A REST API must not define fixed resource names or hierarchies (an obvious coupling of client and server). Servers must have the freedom to control their own namespace. Instead, allow servers to instruct clients on how to construct appropriate URIs, such as is done in HTML forms and URI templates, by defining those instructions within media types and link relations. Most APIs that people call "RESTful" -- regardless of whether they come with an OpenAPI spec -- don't obey HATEOAS. A typical OpenAPI spec describes the possible request paths and verbs. However, you probably wouldn't be able to discover all that information just by starting from the entry point and parsing the `hrefs` in the response bodies.