I do maintain a couple of JSON schemas and they're a bit clunky due to the JSON syntax (although they're nicer in YAML which my validator can use) but the newer

I do maintain a couple of JSON schemas and they're a bit clunky due to the JSON syntax (although they're nicer in YAML which my validator can use) but the newer versions of the spec do allow you do specify complex enough rules to cover most cases. But an equivalent to XSLT doesn't make a huge amount of sense for JSON. I've got an XSLT stylesheet I wrote you can add to an HTML page via the xml-stylesheet directive that turns it into a pretty-printed display of its own markup, complete with syntax highlighting. Pointless but neat that it's possible :)