I know this probably a dumb question but I know that the REST urls one hits in REST parlance are called “resources“.
My question is what should one call the response/request bodies. Should they be called states?
Media Types can’t be right because that is the format (ie XML, or JSON). Maybe “State”?
For now I have been using the term “message”.
The correct term is “representations”. They are snapshots in time of the actual resource referred to by the URI.
REST stands for “Representational State Transfer”, so the answer is right in the name. REST is about the transmission of representations around a system in such a way that work can be done on the real resource on the server side. The encoding of the representation is dictated by the Media Type used for content negotiation.