[extension]

Most any document format can contain links, but that doesn't make it hypermedia. You can't make a client that knows what to do with any JSON or XML document.

[leftnode]

Wait, why not? The JSON could return in a standard format that the client knows where to look for links to other documents.

[extension]

Sure, you can design a standard format on top of JSON, but that is rarely done. The whole appeal of it is for passing around ad-hoc data structures.

There are many hypermedia formats built on XML, but when it's just used as a data container for an API, it's not hypermedia.

[leftnode]

Gotcha, that makes sense. Thanks.