ZSTD file format: what it is and how to use it

Zstandard is Facebook's modern compressor: gzip-level ratios at many times the speed, tunable across a huge range, and the new default of filesystems and pipelines. Learn when to use it and what to choose instead.

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What is a ZSTD file?

A .zst file is a stream compressed with Zstandard, Facebook's 2016 algorithm (RFC 8878) that hit gzip's compression ratio while running several times faster: a wide tunable range from real-time levels to LZMA-class high modes, plus dictionary training for small data. It is the new default inside filesystems (Btrfs, ZFS), databases and, as .tar.zst, modern Unix packaging.

When should you use ZSTD?

  • Pipelines and backups: the best speed-to-ratio trade-off available.
  • Modern Unix archives: .tar.zst replaces .tar.gz wherever zstd exists.
  • Databases and filesystems: the compression layer everything new picks.

When is another format a better fit?

For sharing with non-technical users, ZIP opens without installs. For absolute maximum ratio xz/7z edges it at the cost of speed; for web text Brotli has the HTTP niche. ZSTD is the right default for technical work.

The short version: ZSTD is the modern compressor: gzip's job done faster, and the default for anything you control.

How to open a ZSTD file

On Windows

Double-click the file, or open it with 7-Zip (plugin).

On macOS

PeaZip opens ZSTD files on macOS.

In your browser

Open ZSTD files right in a browser tab or with the dexrr viewer. No install, no upload.

Also opens in

  • zstd CLI
  • 7-Zip (plugin)
  • PeaZip
  • tar --zstd

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ZSTD technical details

Full name
Zstandard compressed file
Extensions
.zst .zstd
MIME type
application/zstd
Magic bytes
28 B5 2F FD
Compression
Lossless
Developer
Yann Collet (Meta/Facebook)
Specification
datatracker.ietf.org

ZSTD questions, answered

How do I open a .zst file?

zstd -d, tar --zstd -xf, 7-Zip and modern archive tools decompress it. dexrr extracts .zst files directly in your browser.

Can I convert ZSTD files online?

Yes, dexrr decompresses .zst and repacks contents locally in your browser to zip, gz or other formats.

Is ZSTD better than GZIP?

On both axes: comparable ratio at several times the speed. Gzip's only remaining edge is universal presence.

What is a .tar.zst file?

A tar archive compressed with zstd, the modern equivalent of .tar.gz: Unix trees with permissions, packed and shrunk quickly.

Is the ZSTD format outdated?

The opposite: it is the actively adopted modern standard, displacing gzip inside filesystems, databases and distributions.