.ZST file signature
A Zstandard compressed data file begins with the bytes 28 B5 2F FD at the start of the file. The signature is the same whatever the file is named, which is why a renamed or extensionless ZST file is still recognisable.
Signature
| Offset | Hex | ASCII |
|---|---|---|
| 0 | 28 B5 2F FDZstandard frame magic. Skippable frames use 50 2A 4D 18 through 5F 2A 4D 18. |
MIME type: application/zstd · usual extensions: .zst
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.zst
file file.zstWindows (PowerShell):
Format-Hex -Path file.zst -Count 32If the bytes do not match
A file named .zst whose first bytes are something else is not a ZST 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 ZST guide explains what a genuine file should contain.