Although not mandatory, the common practice is to return a JSON document in response to a REST request. It is worth noting, at this juncture, that many developers are opting to respond with a formalized JSON document structure based on an emerging standard. We will digress briefly to discuss some of the more commonly used standards.
The first question that doubtlessly comes to mind is why bother with standards for JSON? This is a very good question, for which there is a simple answer: if your RESTful application delivers a standards-based response, it's easier for REST clients to handle, easier to maintain, and extends the application's usefulness over time. The next question is: is there an "official" standard for JSON responses? Unfortunately, the answer to the latter question is no! There are, however, emerging standards, the more popular of which we summarize in this section.