Mime Types

Look up the MIME type (Content-Type) for a file extension, or find which extensions use a given MIME type. The table covers the formats web developers meet most — web pages, scripts, data, images, fonts, audio, video, documents and archives — with notes on charset, legacy types and how to configure your server.

What a MIME type is

A MIME type (also called a media type or content type) is a label such as text/html or image/png that tells software what kind of data a file or message contains. It has a type and a subtype separated by a slash, and sometimes parameters such as charset=utf-8. Web servers send it in the Content-Type HTTP header, and browsers use it — not the file extension — to decide whether to render a page, run a script, display an image or offer a download. The official list of media types is maintained by IANA.

The top-level types

MIME types web developers need most

For JavaScript, text/javascript is the current standard (RFC 9239); application/javascript is still widely seen and accepted. For icons, image/vnd.microsoft.icon is registered but image/x-icon is common in practice.

Why the correct MIME type matters

• Security — with the X-Content-Type-Options: nosniff header, browsers refuse to run scripts or apply stylesheets served with the wrong type, which blocks some attacks.
• Modules and WebAssembly — JavaScript modules and WebAssembly.instantiateStreaming require correct types.
• Downloads — a PDF served as text/plain shows as garbage; an Excel file served as application/octet-stream downloads instead of opening.
• Fonts — some browsers reject fonts with wrong types or without CORS headers.
• Caching and compression — CDNs often decide what to compress by content type.

Setting MIME types on common servers

Nginx reads mime.types and you can add entries in a types { } block, for example application/manifest+json webmanifest;. Apache uses AddType application/wasm .wasm in the configuration or .htaccess. Node.js frameworks usually rely on a MIME library; set res.type() or the Content-Type header explicitly for custom responses. Static hosting and CDNs generally detect types from extensions; check the response headers in your browser’s developer tools (Network tab) to confirm.

Charset and text types

Text-based types should declare their character encoding, almost always UTF-8: Content-Type: text/html; charset=utf-8. Without it, browsers may guess and display accented characters incorrectly. JSON is defined as UTF-8 by its standard, so a charset parameter is not required, though it is harmless.

Worked example

After deploying a progressive web app, the browser console warns that the manifest has the wrong MIME type and WebAssembly fails to stream. Looking up .webmanifest gives application/manifest+json and .wasm gives application/wasm. Adding both to the server’s MIME configuration and redeploying fixes the warnings, and X-Content-Type-Options: nosniff is added so browsers never guess.

Uploads and user files

Never trust the MIME type or extension of a file a user uploads — both are chosen by the client. Validate uploads on the server by checking the file’s actual content (magic bytes), restrict the types you accept, and serve user uploads with Content-Disposition: attachment or from a separate domain, so a disguised HTML or SVG file cannot run scripts on your site.

MIME types in email and APIs

MIME was originally designed for email — the name stands for Multipurpose Internet Mail Extensions — and it is still how email clients know that an attachment is a PDF or an image. Multipart emails use multipart/mixed or multipart/alternative to hold several parts, such as plain-text and HTML versions of the same message. In APIs, clients send an Accept header listing the types they can handle, and servers reply with a matching Content-Type; APIs often use vendor types such as application/vnd.example+json for versioning.

Structured syntax suffixes

Many types end in a suffix such as +json, +xml or +zip, which tells software the underlying format even if it does not know the specific type. application/ld+json is JSON, image/svg+xml is XML, and application/epub+zip is a ZIP archive. Generic tools can therefore still parse or inspect the content.

Privacy

The lookup table is built into this page; searches run in your browser and nothing is sent to a server.