possible resource representations (which will include representation of the data and of the hypermedia links for state transitions) the possible state transitions and where they can occur Discussion Unlike SOAP-based web services, there is no "official" standard for RESTful web APIs. This is because REST is an architectural style, while SOAP is a protocol. REST is not a standard in itself, but RESTful implementations make use of standards, such as HTTP, URI, JSON, and XML. Many developers describe their APIs as being RESTful, even though these APIs do not fulfill all of the architectural constraints described above (especially the uniform interface constraint). Most APIs claiming to be RESTful actually only satisfy the level 2 of the Richardson Maturity Model. See also (DAP) Overview of RESTful API Description Languages Resource-oriented architecture (ROA) Resource-oriented computing (ROC) Service-oriented architecture (SOA) Web-oriented architecture (WOA) References Further reading Cloud standards Hypertext Transfer Protocol Software architecture Web 2.0 neologisms