What is a .zst file?
Zstandard Compressed File · Archive · Meta (Facebook) · 2016
Zstandard (.zst) is a modern compression format that is very fast while still compressing well. It has spread quickly through Linux packaging, filesystems and databases, often seen as .tar.zst.
What is a .zst file used for?
A .zst file begins with the little-endian magic 28 B5 2F FD. Zstd's headline feature is speed: it decompresses far faster than xz at similar ratios, which is why package managers and filesystems adopted it.
As a single-stream compressor it pairs with tar for bundles, giving .tar.zst. Modern archive tools and the zstd command handle it.
What opens a .zst file?
The .zst format opens in the following apps, grouped by operating system. If one app does not work, try another from the same list.
Windows
- 7-Zip (recent)
- PeaZip
- zstd
macOS
- Keka
- zstd (Homebrew)
Linux
- zstd
- tar
- Ark
Open a .zst file step by step
- Confirm the file really is a .zst. Drop it into the WhatFileType identifier, which reads its signature in your browser without uploading anything.
- On Windows, open it with 7-Zip (recent) or PeaZip.
- On Mac, use Keka or zstd (Homebrew).
- On Linux, try zstd or tar.
- Still stuck? Convert the .zst to xz, which opens more widely.
Why can't I open my .zst file?
Almost always because no installed app understands Zstandard. Install one of the apps above, or convert the file to a format your existing software already reads. If double-clicking opens the wrong program instead of nothing at all, the file association is set to the wrong app rather than the file being broken.
The other possibility is that the file is not really a .zst at all. Drop it into the file identifier to check it by its bytes instead of its name. Nothing is uploaded.
How to convert a .zst file
You can convert a .zst file to xz, gz, zip using a conversion tool or the export menu of an app that opens it.
What is the .zst file signature (magic bytes)?
A .zst file starts with the hex bytes 28 B5 2F FD. Programs identify Zstandard by those bytes, not by the filename, so a renamed file still gives itself away.
These are the documented signatures for Zstandard. For a full breakdown, see the Zstandard file signature page.
| Hex signature | Offset | ASCII | Note |
|---|---|---|---|
| 28 B5 2F FD | 0 | - | Zstandard frame magic |
See the full magic-numbers reference for every format.
Frequently asked questions
What is a .zst file?
Zstandard (.zst) is a modern compression format that is very fast while still compressing well. It has spread quickly through Linux packaging, filesystems and databases, often seen as .tar.zst.
How do I open a .zst file?
Use the zstd command (zstd -d file.zst), a recent 7-Zip or PeaZip on Windows, or Keka on Mac. A .tar.zst unpacks with tar --zstd -xf.
Is Zstandard better than gzip or xz?
It decompresses much faster than xz at similar sizes, and beats gzip on both. That speed is why Linux packaging and filesystems switched to it.
What makes .zst files popular?
A rare mix of high compression and very fast decompression, plus tunable levels, which suits package managers, backups and real-time systems.
Related formats
Sources
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