MIME Type Checker

How to use MIME Type Checker

1. Open MIME Type Checker — it runs entirely in your browser with no setup.
2. Paste or type your input into the text area, or upload a file where supported.
3. Set any options you need. The result appears in the output panel — there is no upload step and no waiting on a server.
4. Review the output instantly; large inputs are handled locally without lag.
5. Copy the result to your clipboard or download it. Your data never leaves the page.

Why use MIME Type Checker?

• 100% free with no limits, no sign-up and no watermarks.
• Private by design — your data are processed in your browser and never uploaded to a server.
• Fast and lightweight, with instant results even on a phone or a slow connection.
• Works everywhere — any modern browser on Windows, macOS, Linux, Android or iOS.
• Part of a full developer tools suite, so related mime type checker tasks are one click away.

What people use MIME Type Checker for

• Finding the correct Content-Type to serve for a file extension.
• Diagnosing a download that opens in the browser instead of saving.
• Configuring a server or CDN for an unfamiliar file type.

MIME Type Checker: limits and things worth knowing

• An extension is a hint, not a fact. A file named .jpg can contain anything, which is why extension-based checks are not a security control — use MIME Detector, which reads the actual bytes.
• Serving JavaScript modules as text/plain breaks them in any browser sending X-Content-Type-Options: nosniff. The .mjs extension is missing from several default server MIME tables, and this is a common cause of a module that will not import.
• text/* types should carry a charset parameter; without it a browser guesses, and the guess is not always UTF-8.
• Types prefixed x- are unregistered conventions rather than standards, so support for them varies.

Is it private and secure?

Your privacy is built in. MIME Type Checker runs completely on your device, so whatever you enter stays in your browser and is never transmitted, logged or stored on any server.

Network activity: none. Nothing is sent and nothing is fetched. This tool makes no network request at all once the page has loaded — which is why it keeps working if your connection drops.

You do not have to take that on trust — our privacy proof page publishes the Content-Security-Policy that enforces it, lists every third party it permits, and shows how to verify the whole claim yourself.

Learn more

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