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MIME Type Lookup

Search 24 source-checked media types by extension, format, or MIME string, then copy the exact registered value.

Privacy: your files never leave your device. All processing happens locally in your browser.

How to use

  1. 1.Enter an extension, format name, or media type in the search field.
  2. 2.Confirm the matching description and extension aliases.
  3. 3.Copy the exact base media type and validate it against the real content before use.

About MIME Type Lookup

MIME Type Lookup is a focused reference for 24 media types frequently used in web responses, uploads, downloads, email attachments, and application metadata. Search by a filename extension such as .json, a family such as image, a full value such as font/woff2, or a format description. Each result keeps the extension aliases, media type, and plain-English format label together. Copying a result copies only the media type so it can be pasted directly into a Content-Type header, allowlist, test fixture, or configuration file.

A media type describes the nature and format of bytes. It normally contains a top-level type and subtype separated by a slash, such as image/png or application/json. Parameters may follow in real HTTP headers, but this reference intentionally lists only the base registered type. Charset declarations, boundary parameters, codecs, content disposition, compression, transfer encoding, and content negotiation are separate concerns. Adding charset=utf-8 without understanding the format is not a harmless universal default.

The table uses IANA's media type registry as the authority for registered names and MDN's common-type table to cross-check practical filename associations. Eight external fixtures lock familiar anchors including HTML, CSS, JavaScript, JSON, PNG, JPEG, SVG, and WOFF2. The complete table enforces unique identifiers and media types. It also includes application/octet-stream as the generic fallback for unknown binary data, with no invented extension attached.

Extensions are hints rather than proof. A file named picture.png can contain non-PNG bytes, and a browser-supplied File.type can be empty, stale, or derived from the operating system's extension mapping. Secure upload handling must inspect the content, enforce size and format limits, decode with a safe maintained parser, rename stored objects, isolate them from execution, and apply authorization. Never use this lookup or a request header as the only security decision.

Some extensions legitimately have contextual or historical alternatives. XML may be served as application/xml, while specialized XML formats have dedicated +xml subtypes. JavaScript historically appeared under several legacy values; current web guidance uses text/javascript. A .gz file may be labeled with the registered application/gzip or a platform's nonstandard x-gzip value. The table presents one current common mapping rather than pretending every server, desktop, registry, or historical browser agrees.

Correct Content-Type helps browsers interpret responses and enables protections such as nosniff to work as intended. A wrong type can prevent modules, stylesheets, fonts, media, or downloads from loading; it can also create unsafe content-sniffing behavior. Validate the header on the actual deployed response, not only in framework configuration. For generated or proxied content, preserve the trusted upstream type only when the upstream itself is controlled and verified.

Everything on this page runs locally. Search text is filtered in memory, copying uses the browser clipboard after a click, and no file is opened or uploaded. The reference is deliberately bounded rather than a mirror of the entire IANA registry. Vendor-specific office formats, multipart boundary construction, email transfer encodings, codec parameters, and every obscure registered subtype are outside scope. Follow the linked IANA registry when a format is absent or when standards compliance depends on the newest registration.

For reliable use, locate the desired format, confirm that the content bytes truly match it, copy the registered base type, and test the real response or upload path. Treat unknown content as untrusted binary data and prefer an explicit allowlist over accepting every type in this table. Recheck the primary registry for protocol contracts, because registrations and implementation guidance can evolve independently of this curated set.

Methodology & sources

Stores 24 curated IANA media types with unique IDs and unique base type strings, filters normalized extension/type/description fields, and copies exactly one displayed type. Eight independently authored MDN/IANA fixtures lock common mappings; the generic binary fallback intentionally has no extension.

Frequently asked questions

Can a filename extension prove a file's content type?
No. Extensions and browser-supplied types are hints. Security-sensitive uploads need content validation, strict limits, safe decoding, isolated storage, and authorization.
Why does JavaScript use text/javascript?
Current web specifications and IANA registration use text/javascript; several older application and x-prefixed values remain historical compatibility artifacts.
Does this list contain every registered MIME type?
No. It is a curated set of 24 common mappings. Use the linked IANA registry for formats outside this scope or contracts that require the latest registration.

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