The aim of the research of the model as stated by the author was to find out the relationship between the constraints of REST and other forms of web services.
[1] It divides the principal parts of RESTful design into three steps: resource identification (URI), HTTP verbs, and hypermedia controls (e.g.
[3] The lowest level of the model describes a Web API with a single URI (typically POST over HTTP) accepting all the range of operations supported by the service.
Introduces resources and allows requests for individual URIs (still all typically POST) for separate actions instead of exposing one universal endpoint (API).
Also called HATEOAS (Hypermedia As The Engine of Application State), these are elements embedded in the response messages of resources which can establish a relation between individual data entities returned from and passed to the APIs.