Comment by fauigerzigerk

>But I can't see any angle where one can credibly assert that a SOAP XML payload isn't equivalent to a REST JSON payload in terms of the operation of a receiving application.

I guess the angle is that there was a style of SOAP where the payload was interpreted as a remote procedure call conforming to an interface described in a WSDL document.

So there would be a SOAP library or server infrastructure (BizTalk) on the receiving end that would decode the message and turn it into a function call in some programming language.

In that sense, the payload would be "data" only for the infrastructure code but not on the application level.

And now I'm going to have to spend the rest of the day trying to forget this again :)