File Type Detector

Upload a file to identify its true type by analyzing magic bytes and file signatures. All processing happens locally in your browser.

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How It Works

Most file formats begin with a unique sequence of bytes known as magic bytes or a file signature. This tool reads the first bytes of your file and compares them against a database of known signatures to identify the true file type, regardless of the file extension.

For example, a PNG image always starts with the bytes 89 50 4E 47, while a PDF begins with 25 50 44 46 (%PDF in ASCII). By checking these signatures, you can verify whether a file is genuinely what its extension claims.

Common Uses

• Verify file types before opening untrusted files
• Detect renamed or disguised files
• Identify files with missing or incorrect extensions
• Inspect the raw header bytes of any file