File Type Detector
Detect true file type from magic bytes (signature), not extension. 200+ signatures, MIME type, extension suggestion, and 10+ extras. 100% private.
About File Type Detector
Detect true file type from magic bytes (signature), not extension. 200+ signatures, MIME type, extension suggestion, and 10+ extras. 100% private. Everything runs locally in your browser — your data never leaves your device.
How to use
- Enter your input in the tool above.
- Adjust any options to your preference.
- Use the Copy or Download buttons to save the result.
- Everything happens locally — your data never leaves your browser.
FAQ
How does file type detection work?
The tool reads the first 16-64 bytes of the file and matches against a database of 200+ magic byte signatures (e.g., PNG starts with 89 50 4E 47, PDF with 25 50 44 46). The file extension is ignored — only the actual content matters.
What extras does this tool have?
Extras: (1) 200+ magic byte signatures, (2) MIME type per match, (3) Suggested extensions, (4) Confidence score, (5) Match against declared extension (mismatch warning), (6) Show all matching signatures, (7) Show first 64 bytes as hex dump, (8) Batch multiple files, (9) CSV export of batch results, (10) Copy individual results, (11) Detect text vs binary, (12) Show file size, (13) Detect archive types (zip, rar, 7z, tar, gz), (14) Detect image format dimensions when possible.
Related tools
7Z Extractor
Inspect and extract files from 7z archives. Detects the 7z signature (0x37 0x7A 0xBC 0xAF 0x27 0x1C), parses the SignatureHeader and StartHeader, lists files from the archive metadata, and extracts STORE-method files when possible. Honest about LZMA compression limitations. 100% client-side.
APK Extractor
Extract and inspect Android APK files in the browser — pure JavaScript APK (ZIP) parser. View AndroidManifest.xml (binary XML detection), list DEX files, resources, and assets, extract individual files, detect app info (package name, version) from manifest. 100% client-side.
ARJ Extractor
Inspect ARJ archives. Detects the ARJ magic (0x60 0xEA), parses header structures, lists file entries with sizes and CRCs, and extracts STORE-method files when possible. Honest about ARJ compression limitations. 100% client-side.