.LZ4 file signature
A LZ4 compressed data file begins with the bytes 04 22 4D 18 at the start of the file. The signature is the same whatever the file is named, which is why a renamed or extensionless LZ4 file is still recognisable.
Signature
| Offset | Hex | ASCII |
|---|---|---|
| 0 | 04 22 4D 18LZ4 frame format. Legacy frames use 02 21 4C 18. |
MIME type: application/x-lz4 · usual extensions: .lz4
How to check a file's signature
Without installing anything: drop the file on our detector. It reads the bytes in your browser and shows the hex dump alongside the verdict; nothing is uploaded.
macOS and Linux (Terminal):
xxd -l 32 file.lz4
file file.lz4Windows (PowerShell):
Format-Hex -Path file.lz4 -Count 32If the bytes do not match
A file named .lz4 whose first bytes are something else is not a LZ4 file. The common explanations are a wrong or deliberately misleading extension, a download that saved an HTML error page instead of the file, or a container such as ZIP wrapping the real content. The detector reports what the bytes say; the LZ4 guide explains what a genuine file should contain.