FILE TOOL // 026

MIME Type Detector

Check what a file appears to be by comparing its extension, browser MIME label, and signature bytes. Conflicts are clearly reported instead of silently trusting the filename.

Processed locally in your browser

Choose files to identify

One or more files

Drop files here Drop files to compare extensions, MIME labels, and magic bytes.

FileSizeType

No files selected.

Choose files to begin.0 files

How to use MIME Type Detector

Select One or more files using the file area.
Review the selected filenames and sizes.
Choose any available options and click Detect MIME Types.
Read the findings, then download the JSON MIME report.

What this file tool does

Examines leading bytes for common file signatures and compares that evidence with the browser-reported type and file extension.

Magic-number rules identify PDF, PNG, JPEG, GIF, ZIP, GZIP, WebP, MP3, MP4, and executable signatures. Results are exported as JSON.

Your selected files stay in this browser session. Not every format has a unique header, and ZIP containers may hold DOCX, XLSX, EPUB, or other formats. Unknown does not mean unsafe.

Supported inputs and limits

Not every format has a unique header, and ZIP containers may hold DOCX, XLSX, EPUB, or other formats. Unknown does not mean unsafe.

Item	Support
Input	One or more files
Output	JSON MIME report
Processing	Local browser session

Example and practical tips

Practical example

A file named photo.jpg with a PDF signature is marked as a conflict so you can investigate before opening it.

Tips

Keep an untouched copy of important source files.
Check filenames and sizes before downloading the result.
Use a current desktop browser for the broadest file API support.

Frequently asked questions

How can I use mime type detector without uploading files?

Choose the requested files in this page and run the tool. Processing happens in your browser, and only the result you download leaves the page.

What does the downloadable json mime report contain?

It contains the actual result or evidence produced from the selected file bytes and metadata, with the important findings shown on screen as well.

Can I use mime type detector on a large file?

Browser memory and device speed set the practical limit. Start with a smaller sample if the file is several gigabytes or the device has limited memory.

Does this tool change my original files?

No. Browser file access is read-only here. The tool creates a separate result for download and does not overwrite the selected originals.

Is a clean result a complete security guarantee?

No. The result covers the checks described on this page. Use specialized desktop or forensic software when you need deeper validation.

Related file tools

File Hex Viewer File Metadata Privacy Scanner Binary File Compare Double Extension Detector

Result details

Field	Meaning
Primary result	Main finding from the selected files
Download	JSON MIME report
Status	Complete only after a real result Blob is created

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