MIME type lookup · Guide
MIME Type Lookup Online
A MIME type lookup maps a file extension to its content type and back. This guide explains what MIME types are for and where you need them.
Extensions and content types
A MIME type like application/json or image/png tells software how to interpret a file or response body. The lookup converts between a familiar extension (.json) and its MIME type in either direction.
Where MIME types matter
They drive the Content-Type header on responses, validation on uploads, and how browsers decide whether to display or download a file. Getting the type right avoids files being mishandled.
Frequently asked questions
Why does the MIME type matter for uploads?
Servers and browsers use the MIME type to decide how to handle a file. A wrong or missing type can cause uploads to be rejected or files to be treated as the wrong format.
Ready to try it?
Open the free browser-based MIME type lookup and apply what you just read — no sign-up, runs locally.
Open the MIME type lookup tool