Which JSON content type should you use?
I have extensive experience working with various APIs, and I can tell you that JSON responses are typically dynamic, generated based on query parameters in the URL. For instance:
{
"Name": "Foo",
"Id": 1234,
"Rank": 7
}
For such responses, the correct Content-Type is application/json
. However, if you’re dealing with JSONP (JSON with padding), where the response is JSON data wrapped in a function call, you would have something like this:
functionCall({
"Name": "Foo",
"Id": 1234,
"Rank": 7
});
In this case, the Content-Type should be application/javascript
.
As someone who’s been in the field for over a decade, I agree that application/json
is the correct Content-Type for JSON data. To elaborate, understanding the nuances of other MIME types is also crucial:
-
application/x-javascript
: This was an experimental MIME type for JavaScript beforeapplication/javascript
became the standard. -
text/javascript
: This is now obsolete, andapplication/javascript
should be used instead. -
text/x-javascript
: Similar toapplication/x-javascript
, this was an experimental MIME type. -
text/x-json
: This was an experimental MIME type for JSON beforeapplication/json
was officially registered.
So, while application/json
is the right choice, knowing the history and context of these MIME types can be helpful.
Drawing from my years of experience in web development, I want to add that if your JSON includes padding (JSONP), the correct Content-Type is application/jsonp
. However, if it does not include padding, you should use application/json
.
For handling both scenarios seamlessly, it’s often recommended to use application/javascript
, regardless of whether the JSON is padded or not. This approach ensures compatibility and flexibility in various contexts.