MIME Type Lookup

A MIME type, also called a media type, is a short label like text/html or image/png that tells software what kind of data a file holds. The part before the slash is the general category and the part after is the specific format.

When a server sends a file, it sets a Content-Type header to the file's MIME type. The browser reads that header to decide how to handle the response, for example rendering HTML, showing an image or downloading a binary.

Browsers trust the declared MIME type over the file name. Send CSS as text/plain and the page will not style; send a script with the wrong type and strict browsers will refuse to run it. The right type keeps assets working and avoids security blocks.

Many formats have more than one common extension. For example jpg and jpeg are both image/jpeg, and yml and yaml are both application/yaml. The reverse lookup lists every extension that shares a type.

These are the IANA registered or most widely used types for each extension. A few formats have competing types in the wild, so always confirm against your server or framework defaults if behavior looks off.

No. The extension and MIME type tables are bundled with the page, so every lookup happens locally in your browser and nothing is uploaded.