MIME Type Lookup

Finding the right content type

A MIME type (now called an Internet media type) is a two-part label like image/png or application/json that tells a server, browser, or library how to interpret a chunk of bytes. It's what goes in HTTP Content-Type headers, what Multipart message parts declare, and what file --mime reports. The IANA registry has thousands of entries; this tool covers roughly 120 common ones you'll actually encounter in web development, APIs, and file handling.

Headers, uploads, and server config

• Setting Content-Type on an API response and needing the correct type for .docx, .heic, .webmanifest, or other less obvious formats.
• Configuring an upload field's accept attribute in HTML or an S3-bucket allow-list policy.
• Reading HTTP headers, tcpdump output, or logs and looking up what application/grpc-web or application/ld+json actually is.
• Building a static-file server, CDN config, or reverse-proxy routing rules that require extension-to-MIME mapping.
• Settling format debates — for example, whether to use text/xml or application/xml (RFC 7303 recommends the latter for new code).
• Debugging browser download or rendering issues caused by mismatched or missing Content-Type headers.

Extension to MIME and back again

• Search by extension: Enter a file extension like .pdf, .mp4, or .woff2 and get the standard MIME type back.
• Search by MIME type: Enter a full or partial MIME type like image/ or application/json to find all matching entries and their file extensions.
• Copy to clipboard: Click or tap any result to copy the MIME type or extension to your clipboard — useful when building headers or config files.
• Browse by category: Results are grouped by media type category (image, video, audio, application, text, font) so you can explore related formats at a glance.

Mismatches that break downloads and rendering

• Extension does not equal MIME type. A .json file usually maps to application/json, but a misconfigured server can serve it as text/plain and browsers will obey the header. Always set Content-Type explicitly in your code.
• JavaScript has legacy baggage. RFC 9239 designates text/javascript as the official type. However application/javascript, application/ecmascript, and other variants are still widely used and supported; old browsers expect them.
• OOXML types are extremely verbose. .docx maps to application/vnd.openxmlformats-officedocument.wordprocessingml.document — do not try to memorise these. Look them up or copy them.
• application/octet-stream means "unknown". Browsers treat it as a force-download and will not attempt to render it, even for formats like PDFs or images. Use a proper MIME type if you control the content.
• Charset must be declared for text types. Content-Type: text/html; charset=utf-8 — omitting the charset allows browsers to guess, leading to mojibake (garbled characters) in non-ASCII content.
• Content-Type sniffing can override your header. Some browsers inspect file magic bytes and may render content differently than your declared type. Set X-Content-Type-Options: nosniff to prevent this; it improves security.

What the table covers (and what it doesn't)

• This tool indexes roughly 120 of the most common MIME types used in web development, APIs, and file transfer. The IANA registry is much larger and includes experimental and vendor-specific types.
• For exhaustive or specialist types (e.g., medical imaging, rare font formats, niche document standards), consult the official IANA Media Types registry at iana.org/assignments/media-types.
• Vendor prefixes like vnd. and x- indicate non-standard or private types; they are included here where widely adopted (e.g., application/vnd.api+json for JSON:API).

The type/subtype label and the IANA registry

A MIME type — now formally an Internet media type — is a two-part type/subtype label like image/png or application/json that tells a browser, server, or library how to interpret a stream of bytes. It's what fills the HTTP Content-Type header, what each part of a multipart upload declares, and what file --mime reports. The IANA registry lists thousands; this table covers roughly 120 you'll actually meet across web development, APIs, and file handling. Search works both directions — type an extension (.pdf, png, .json) or a type fragment (image/, video) — and clicking any result copies it to your clipboard for pasting into a header or config.

Forced downloads, charsets, and OOXML verbosity

Why does my file download instead of displaying? Almost always the wrong Content-Type. The classic culprit is application/octet-stream, the "generic unknown binary" type — browsers treat it as a forced download and won't try to render it, even for a PDF or image. If you control the response, send the real type.

text/javascript or application/javascript? Use text/javascript. RFC 9239 (2022) made it the preferred, registered type for JavaScript; application/javascript is now legacy and kept only for compatibility.

Do I need a charset? For text-based types, yes — append it: text/html; charset=utf-8, text/csv; charset=utf-8. It removes any ambiguity about byte decoding. Binary types (images, PDFs, archives) carry no charset, and application/json is defined as always UTF-8, so a charset there is redundant.

Why are the Office (OOXML) types so long? A .docx is application/vnd.openxmlformats-officedocument.wordprocessingml.document — that verbosity is the real registered name. Don't memorise them; look them up here and copy the exact string, because a single typo makes the file unrecognised.