The REST constraints tell us to design APIs according to HATEAOS (Hypertext as the Engine of Application State). The Richardson Maturity Model rates APIs according to the fulfillment of these constraints and assigns the highest rating (level 3) to the
Richardson Maturity Model – classify REST-like APIs
Not every service that is exposed over HTTP is compliant with the REST constraints. Sometimes one can find services, which are advertised as being RESTful, but in reality, they follow the RPC style. In fact, there may even be a