A MIME type, also called a media type or Content-Type, is a two-part label like image png that tells software what kind of data a file or HTTP response contains. Browsers use it to decide how to handle a resource.

Why does the wrong MIME type break my page?

Browsers increasingly enforce the declared type. Serving JavaScript as text plain, or a module with the wrong type, can cause the browser to refuse to execute it. Always send the correct Content-Type from your server.

What MIME type should I use for an unknown binary file?

Use application octet-stream. It signals arbitrary binary data and usually prompts the browser to download the file rather than try to display it. It is the safe default when no specific type applies.

Are .doc and .docx the same MIME type?

No. The legacy .doc format uses application msword, while the modern .docx format uses a long OpenXML type ending in wordprocessingml.document. Office formats changed types when they moved to the zipped XML container.

Where do these MIME types come from?

They follow the IANA media types registry, which is the authoritative list, plus the de-facto values that browsers and web servers use in practice. The two agree for almost all common formats.

MIME Type Reference — Gera Tools

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Look up the right Content-Type fast

A MIME type (media type) is the label that tells a browser or server what kind of data a file holds — image/png, application/json, video/mp4, and so on. Sending the correct Content-Type header matters: get it wrong and browsers may refuse to run scripts, fail to render images, or download files you wanted displayed. This tool maps common file extensions to their registered MIME types so you can copy the exact value you need.

How it works

Each entry pairs a file extension with the MIME type that the IANA media-types registry assigns to it, alongside the value web servers and browsers use in practice. A MIME type has two parts: a top-level type such as text, image, audio, video, or application, and a subtype such as html, png, or json. The search matches your query against the extension, the full MIME type, and the description, so you can look up by any of them.

Tips and notes

Use application/octet-stream as the safe default for arbitrary binary data — it tells the browser to download rather than guess. Modern Office formats (.docx, .xlsx, .pptx) use long OpenXML types that differ from their legacy counterparts (.doc, .xls, .ppt). JavaScript should be served as text/javascript, and fonts use the font/* family (font/woff2, font/ttf). When configuring a server, set the Content-Type header to the value shown here. All lookups run locally in your browser.