I agree absolutely; if you're using HTTP, you must take into account HTTP semantics. Exactly as you said. But HTTP is not REST (note that SOAP usually layers

I agree absolutely; if you're using HTTP, you must take into account HTTP semantics. Exactly as you said. But HTTP is not REST (note that SOAP usually layers over HTTP, although the SOAP-vs-REST is an unhelpful dichotomy). As some other commenters (including an uncle of this comment) have said, what one often wants is simply RPC, and one must pick (or roll) an RPC format. JSON-or-whatever over HTTP seems good to me, and yes one must be respectful of HTTP semantics. In fact, aside from the very-troubling choice of GET for commands, the API linked seems entirely reasonable. And it's not RESTful at all (in ways far deeper than verb choice). And that's a good thing.