File Magic Byte Identifier
Identify the real file type from magic-byte signatures in your browser.
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Identify a File by Its Actual Content
- Add your files: Drag and drop files onto the panel or use the file picker — multiple files are supported and nothing leaves your browser.
- Read the detection result: Each file shows the detected type name, MIME type, candidate extensions, and size, based on the first 4 KB of actual content rather than the filename.
- Check the extension match: The Match, Mismatch, or Unknown badge compares real content with the declared extension, and the hex preview shows the leading bytes behind the verdict.
- Save the report: Press Download report to export file-detection-report.txt with every file, its detected type, and its status for your records or a security ticket.
Key Features
- Detects 40+ file formats from magic-byte signatures, fully offline
- Spots fake or renamed extensions with a clear match / mismatch verdict
- Batch mode: scan multiple files at once with per-file results
- Hex view of the first 32 header bytes of every file
- Copy or download a plain-text detection report
Frequently Asked Questions
How does the tool identify a file type?
It reads only the first 4 KB of each file and matches the leading bytes against a built-in magic-number signature database — PDF, PNG, ZIP, MP4, SQLite, Windows EXE, ELF, WebAssembly, and dozens more — independent of the filename.
What does the Mismatch status mean?
The detected content type does not agree with the declared file extension, a classic sign of a renamed, spoofed, or corrupted file — for example an .exe renamed to .pdf or a phishing page saved as .jpg.
Can I check several files at once?
Yes — drag and drop a batch or pick multiple files, and each result shows the detected type, MIME type, possible extensions, file size, and a hex preview of the first 24 bytes with a Match, Mismatch, or Unknown badge.
Are my files uploaded anywhere?
No — inspection happens entirely in your browser through the File API, so confidential documents never leave your machine, and the report can be saved locally as file-detection-report.txt.