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How MIME Type Lookup works

  1. Type a file extension (like json) or a full filename (like data.json) into the Input box.
  2. The tool extracts the extension automatically and looks it up in its built-in table.
  3. The Output panel shows the matching Content-Type value, or reports the extension as unrecognized.
  4. Copy the MIME type for use in an HTTP header, upload validator, or config file.
  • Look up the correct Content-Type header value when configuring a file upload endpoint.
  • Confirm the MIME type to set for a static asset served from a custom web server config.
  • Check what Content-Type a browser or API client should expect for a given file extension while debugging.
  • Quickly reference common MIME types while writing API documentation or validation logic.

The extension or filename you type is matched entirely in your browser against a local lookup table — nothing is sent to a server.

  • The lookup table covers a curated set of common extensions only — it is not a complete IANA MIME type registry and will report many valid extensions as unknown.
  • It matches on the extension text alone; it does not inspect actual file content or magic bytes to verify the real file type.
  • It looks up one extension at a time; there's no batch lookup for a list of filenames.

MIME Type Lookup

MIME Type Lookup maps filenames and extensions to common Content-Type values. It is useful when configuring uploads, static assets, APIs, and HTTP headers.

MIME Type Lookup Runs locally

MIME Type Lookup

Look up common MIME types from file extensions or filenames. Everything runs locally in this tab.

Output
json: application/json
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Guide

How to use

  1. Type a file extension (like json) or a full filename (like data.json) into the Input box.

  2. The tool extracts the extension automatically and looks it up in its built-in table.

  3. The Output panel shows the matching Content-Type value, or reports the extension as unrecognized.

  4. Copy the MIME type for use in an HTTP header, upload validator, or config file.

Scenarios

Use cases

  • Look up the correct Content-Type header value when configuring a file upload endpoint.

  • Confirm the MIME type to set for a static asset served from a custom web server config.

  • Check what Content-Type a browser or API client should expect for a given file extension while debugging.

  • Quickly reference common MIME types while writing API documentation or validation logic.

Good to know

Limitations & Privacy

Private by design

The extension or filename you type is matched entirely in your browser against a local lookup table — nothing is sent to a server.

  • The lookup table covers a curated set of common extensions only — it is not a complete IANA MIME type registry and will report many valid extensions as unknown.

  • It matches on the extension text alone; it does not inspect actual file content or magic bytes to verify the real file type.

  • It looks up one extension at a time; there's no batch lookup for a list of filenames.

FAQ

Frequently asked questions

Is MIME Type Lookup free to use?

Yes. The tool is free and runs directly in your browser with no account required.

Does this tool upload my data?

No. Processing happens locally in the browser tab. Your input is not sent to a server.

What is this tool best for?

Quickly confirming the Content-Type header value for a common file extension when configuring an upload handler, API response, or static file server.

How many file types does it recognize?

It covers a curated set of common web and document extensions — html, css, js, json, csv, txt, xml, pdf, png, jpg/jpeg, webp, svg, mp4, zip, and wasm. It is not an exhaustive IANA MIME type registry.

Can I paste a full filename instead of just the extension?

Yes — type a full filename like report.pdf or photo.jpeg and the tool extracts the extension after the last dot automatically.

What happens with an unrecognized extension?

It returns 'Unknown MIME type for .ext' rather than guessing — this tool only reports types from its built-in list, it doesn't infer types from unlisted extensions.

Is the lookup case-sensitive?

No — extensions are lowercased before matching, so .JPG, .Jpg, and .jpg all resolve to the same result.

Does it inspect the actual file content to detect its type?

No. It only looks at the extension text you type — it does not read file bytes, magic numbers, or actual file content, so a mislabeled extension will return the type for that extension, not the file's real format.