What is a MIME type and why does it matter?
A MIME type is a standard label like image/png or application/json that tells software what kind of content a file contains. It is the reason a browser opens a JPG instead of downloading it, the reason a PDF renders inline, and a frequent source of upload errors when it is wrong.
The anatomy of a MIME type
A MIME type has two parts: a main type that groups broad categories — text, image, audio, video, application — and a subtype that names the exact format. The pair is separated by a slash, so image/webp says 'an image in WebP format'.
Sticking to the registered label matters: a browser checks it when deciding how to handle a file, and mislabeling an upload as application/octet-stream forces a download instead of an inline preview.
Common MIME types you will meet
The ones that show up most often are text/html and text/css for web pages, text/javascript for scripts, image/png and image/jpeg for graphics, application/pdf for documents and application/json for API data.
- text/html — web pages.
- text/css, text/javascript — styling and scripts.
- image/jpeg, image/png, image/webp — common image formats.
- application/json — API payloads.
Look up any extension with FreetoolsY
The MIME Type Finder answers two questions. Enter an extension like svg and get its label instantly, or search the other direction — a type like audio — and see every matching extension. Useful when configuring a server, validating uploads or writing API contracts.