Well... as far as I know, json by itself is just objects with fields, these fields are either objects or string values. Of course you can do all you mention but

Well... as far as I know, json by itself is just objects with fields, these fields are either objects or string values. Of course you can do all you mention but you'll have to build a convention on top of json. So reading these json payload would require more than just knowledge of json, it would also require knowledge of what are these fields or objects that carry special interpretation meaning and what to do about it. A lot of these conventions are available the XML standards. Of course if they had started with something like json the result would be less verbose but maybe not that simple either.