Well, you use Invoke-RestMethod for JSON/XML stuff.

Or decide yourself for Invoke-WebRequest to pipe it with whatever the data: ConvertFrom-{JSON,XML,CSV}

With Invoke-WebRequest you get back headers, raw response, etc - and you get to decide whats next. With the RestMethod - just the content as an object.

There is an param to declare response type parsing and if you want to use different parsing. Older versions of powershell use IE and webrequest will randomly barf. It really sucked. You can also use a rest request method that uses json.net to deserialize I believe .