MIME Types Reference and Lookup

Frequently asked questions

What is a MIME type?

A MIME type (also called a media type or content type) is a short label like text/html or image/png that tells software what kind of data a file or HTTP response body contains. It has a top-level type (text, image, application, and so on) and a subtype (html, png, json). Browsers and servers use it to decide how to render or handle content, which is why the Content-Type header often matters more than the file extension on the web.

What is the difference between a MIME type and a content type?

They are the same thing in practice. MIME type is the older name, from the email MIME standard. Media type is the name IANA now uses for its registry. Content type is what the HTTP header is called (Content-Type). When someone talks about a content type header, they mean the MIME type sent with a request or response.

How do I find the right MIME type for a file extension?

Search the table by extension. Type png or .png to surface image/png, or json to surface application/json. The mapping is not one to one: a single extension can have more than one accepted type, and one type can cover several extensions. When in doubt, prefer the type recommended by IANA or MDN for that format.

Why does application/octet-stream show up so often?

application/octet-stream is the generic fallback for arbitrary binary data. Servers send it when they do not know or do not want to declare a specific type, and browsers usually respond by downloading the file rather than displaying it. If a file downloads instead of opening in the browser, a missing or generic Content-Type is a common cause.

What is the correct MIME type for JavaScript?

The current standard is text/javascript, restored by the WHATWG HTML specification. You will still see application/javascript and older forms like application/x-javascript in the wild, and browsers accept them, but text/javascript is the recommended value today. For JSON data use application/json, and for JSON-LD linked data use application/ld+json.

Do MIME types need a charset parameter?

Text formats can carry a charset parameter, for example text/html; charset=utf-8. It tells the client how to decode the raw bytes into characters. For HTML, CSS, and plain text, declaring charset=utf-8 avoids garbled output. Binary types like image/png do not use a charset, and JSON is always UTF-8 by specification, so a charset parameter is unnecessary there.