When XML messages started being used in the late 90s, "old guys" like me recoiled in horror. We knew better - we had been using IDL, which is just like today's "revolutionary" protocol buffers. But the young folks thought that XML was cool.

Then the young folks realized how horrible XML messages really are, and so they created JSON.

And some guy created YAML - another horror.

These syntaxes violate core rules of good software engineering - lack of type safety, lack of composability.

And this is why Amazon has a mess on its hands right now - because they built their infrastructure around JSON and YAML: https://www.linkedin.com/pulse/infrastructure-code-joke-cliff-berg

and this is why Google invented protocol buffers - to escape the JSON message hell.

We have come full circle, back to essentially what people were using in the late 90s. Look up IDL and IIOP.