File Type Detector — Detect Real File Format Online

Identify a file's true format by reading its magic bytes — not its extension. 100% browser-based, no upload required.

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Features

🔍

Magic Bytes Detection

Reads the raw binary header of each file to identify its true format — PNG, JPEG, PDF, ZIP, MP4, and 100+ more types.

⚠️

Disguised File Alert

Compares detected format against the declared file extension and flags mismatches in red — catch malicious or renamed files instantly.

🖥️

HEX + ASCII Dump

Click any result to expand a HEX dump showing the first 256 bytes, with magic bytes highlighted in yellow for easy identification.

📦

Batch Processing

Upload multiple files at once via drag-and-drop, click, or Ctrl+V paste. All files are processed in parallel and shown in order.

🔒

100% Private

Files are processed entirely in your browser using the file-type library. No data ever leaves your device.

🌓

Dark Mode & Mobile Ready

Clean, responsive interface with full dark mode support, optimized for both desktop and mobile use.

How to Use

1

Upload your file(s)

Drag and drop one or more files onto the upload area, click to browse, or paste a file from your clipboard with Ctrl+V.

2

View detection results

Each file shows a result card with its declared extension, detected MIME type, and a green (match) or red (mismatch) indicator.

3

Inspect the HEX dump

Click any card to expand the HEX dump view, showing the first 256 bytes with magic signature bytes highlighted.

Frequently Asked Questions

What are magic bytes?
Magic bytes (or file signatures) are specific byte sequences at the start of a file that identify its format. For example, PNG files always start with 0x89 0x50 0x4E 0x47. This tool reads these bytes to determine the true file type regardless of the extension.
Is this tool free?
Yes, completely free with no sign-up required. All detection runs in your browser.
Are my files uploaded to a server?
No. Files are processed entirely on your device using browser APIs. Only the first 4096 bytes are read for detection, and nothing is sent to any server.
What file formats can it detect?
The tool uses the file-type library which supports 100+ formats including PNG, JPEG, GIF, WebP, PDF, ZIP, DOCX, XLSX, MP4, MP3, MKV, FLAC, EXE, PSD, and many more.
Why would a file's extension differ from its actual format?
Files can be deliberately renamed to disguise their true content (e.g., malware hidden as a .jpg), accidentally renamed, or created by software that assigned the wrong extension. This tool helps you spot such discrepancies.

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