MIME Type Lookup

The MIME Type Lookup tells you the correct content type for a file extension, and can also show which extensions are associated with a given MIME type. The content type is what tells a browser or a server how to handle a file, so it decides whether a document is rendered as a web page, downloaded as a file, or displayed as an image. Use it when you are configuring a server, fixing a response that opens as the wrong kind of content, or setting up the headers on an API. The tool maps a built in list of extensions locally in your browser, so nothing is transmitted. A media type, commonly called a MIME type, is the label a server attaches to a response so the receiver knows how to handle the bytes. It is the difference between a browser rendering a document, displaying an image, or offering a download, and it decides which applications are invoked and how content is treated for security purposes. The type is usually derived from the file extension, which is why a lookup between the two is a constant need: a new asset format is added and the server has to be taught about it, a response arrives as a download when it should render or vice versa, or a static file host needs an explicit mapping because its default list is incomplete. The mapping table itself is standardised, so the correct value for a given extension is a matter of fact rather than judgement. A useful related check is the reverse direction, seeing which extensions are associated with a type, because that clarifies why an upload is being rejected or why a server is guessing the wrong type from an ambiguous extension. The lookup runs locally from a built in list.

📘 Related guide: Look up MIME types by file extension →