Look up MIME types from file extensions or find the extension for a MIME type using a built-in table of 44 common web, image, document, and media mappings offline.
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Quick answer: MIME Type Lookup — File extension ↔ MIME Free, no signup, runs in your browser. See below for the interactive tool, 4-step guide and FAQs.
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Query either direction using a dotted extension such as .json or a full type such as image/png. For example, .png returns image/png, while application/pdf returns .pdf. The built-in table covers 44 common web, image, font, audio, video and office types, enough for routine Content-Type checks without leaving the page.
It covers 44 mainstream web, image, font, audio, video and office extensions. For instance, html, css, js, png, webp, woff2 and docx resolve directly, but the table is not a complete IANA registry and does not include usage notes. All lookups execute inside this tab with no upload; consult IANA for exotic formats.
Unlisted extensions and MIME types show a no-match message instead of a guessed fallback. For example, .xyz returns no match rather than application/octet-stream, while familiar web and office types resolve directly. Check IANA or your server configuration for missing pairs, and validate any generic binary type in staging before serving downloads.
Browsers that sniff content despite declared types may execute masqueraded scripts hidden inside images. For example, uploading evil svg labelled as png could trigger script runs when served loosely. Always send accurate Content-Type and nosniff headers, validate uploads by magic bytes, and isolate user files on separate domains to contain cross-site scripting fallout.
This lookup bridges filename suffixes and media types for accurate Content-Type delivery. Example: .png yields image/png for raster images, application/pdf yields .pdf for document downloads, and .json yields application/json for APIs. The built-in table holds 44 common web, image, font, audio, video and office pairs. Engineers can use the result in Apache, Nginx or upload validators, where an accurate label supports correct previews, caching and compression. The table is a quick reference, not a complete registry, so verify uncommon formats against IANA before deployment.
Reference mapping table: dot png maps image png | dot webp maps image webp | dot woff2 maps font woff2 | dot pdf maps application pdf | dot json maps application json | dot mp4 maps video mp4. Type either side to reveal the counterpart. The reverse lookup returns the first extension that maps to a type, so image/jpeg resolves to .jpg before .jpeg and text/javascript resolves to .js before .mjs. For instance, AddType image/webp .webp repairs Apache delivery. Edge case: an unlisted value returns a no-match message rather than a fallback, so check IANA for exotic formats. Copy results into server blocks, test with curl header inspection, then monitor devtools network panel for correct rendering. Confirm the declared type with a response header or the browser network panel before deployment.
Enter .webp to receive image/webp for modern headers, then query image/png to retrieve .png for an upload allowlist. A second check can confirm that .woff2 maps to font/woff2 for preload hints. Matching ignores case, trims whitespace and accepts a leading dot on extension input. The table does not cover every IANA alias: application/javascript, for example, is absent even though text/javascript maps to .js. Results are reference pairs only, so write the server directive yourself. Press copy to place either value on the clipboard. Limitation: the catalog emphasizes common deployment types, so rare scientific formats may be missing and need IANA confirmation. For URL component breakdowns, see /url-parser; for archive labels, see /zip-creator.