.zst MIME type
Zstandard filearchives
application/zstdZstandard-compressed files (RFC 8878): gzip-like speed with much better ratios.
| MIME type | application/zstd |
|---|---|
| Extensions | .zst |
| Content-Type | application/zstd |
| Compress in transit? | No — already compressed |
| File signature | 28 B5 2F FD |
Good to know
- Zstandard also works as HTTP compression — Chromium and Firefox accept
Content-Encoding: zstd. That's separate from serving a.zstdownload asapplication/zstd; see Content-Encoding. .tar.zstis now common for distribution packages, including Arch Linux's.
Serve .zst files with the right type
The response header to send:
Content-Type: application/zstd
Most servers pick the type from the file extension. If yours sends the wrong one, map it explicitly:
nginx (inside the types block in mime.types)
application/zstd zst;
Apache (.htaccess or server config)
AddType application/zstd .zst
Express
res.set("Content-Type", "application/zstd");Python
import mimetypes
mimetypes.add_type("application/zstd", ".zst")HTML file input
<input type="file" accept=".zst,application/zstd">
Check it
See what a server sends for a file, and what type a local file really is by its contents:
curl -sI https://example.com/file.zst | grep -i '^content-type:' file --mime-type file.zst
Frequently asked questions
What is the MIME type for .zst files?
application/zstd.
What Content-Type header should a .zst file be served with?
Content-Type: application/zstd. It's already compressed, so servers shouldn't gzip it.
How can I tell if a file is really a .zst?
Check its bytes rather than the extension: ZST files start with 28 B5 2F FD. On the command line, file --mime-type name.zst does this for you.
Related types
Headers that go with it: Content-Type · Content-Disposition · X-Content-Type-Options