[PaulHoule]

People complain about any system which is more complex and performant than plain ordinary JSON. Remember how Microsoft pushed "Web Services" and introduced AJAX where the last letter was supposed to be XML?

Microsoft could make the case that many many features in Web Services were essential to making them work but people figured out you could just exchange JSON documents in a half-baked way and... it works.

[blackoil]

X in AJAX stands for XMLHttpRequest, which was predecessor of fetch API. It was originally used for XML in Outlook Web but wasn't tied with it. You can send any content type with it. Also it was for async web, I don't remember it had much relation to web services. Maybe SOAP, but that wasn't MS.

In case of gRPC I believe specs are tied to protobuf but I have seen thrift implementation also.