Which is the parent's point. The actual content type you are sending is irrelevant. HTML, JSON, CSV, it is all the same from a computer's point of view. What i

Which is the parent's point. The actual content type you are sending is irrelevant. HTML, JSON, CSV, it is all the same from a computer's point of view. What is relevant is that the content's structure remains stable. If you are sharing URLs, the structure of the 'API formats' and the structure of the HTML page should be consistent with each other, which means that any big changes to the HTML form could potentially break the API across every format in order to maintain that consistency. If you are going to make your JSON structure stable but then radically change the structure of your HTML page at the same address, then the URI becomes a misnomer and you've lost the reason for having the same resource address for multiple content types in the first place.