Perhaps in part, yes. But cowboy does have a very powerful REST handler built into it that does a lot of the same things: https://ninenines.eu/docs/en/cowboy/2.1/guide/rest_flowchart...

nothing "REST" about it. 100% HTTP

PS: if anyone is interested in a language-agnostic artifact like cowboy's or webmachine's, see https://github.com/for-GET/http-decision-diagram