Zstandard compressionBaseline · Newly available
Zstandard or zstd is a fast lossless compression algorithm. When used as a content encoding, it is often faster and offers better compression than brotli.
Works in the latest version of every major browser, but older devices may not support it yet. Baseline since Feb 11, 2026.
Browser support
DesktopChrome
1–122Not supported
123+Supportedsince Mar 19, 2024
Current: 155Edge
12–122Not supported
123+Supportedsince Mar 22, 2024
Current: 154Firefox
1–125Not supported
126+Supportedsince May 14, 2024
Current: 157Safari
1–26.2Not supported
26.3+Supportedsince Feb 11, 2026
Current: 27MobileChrome Android
18–122Not supported
123+Supportedsince Mar 19, 2024
Current: 155Firefox Android
4–125Not supported
126+Supportedsince May 14, 2024
Current: 157Safari iOS
1–26.2Not supported
26.3+Supportedsince Feb 11, 2026
Current: 27How to use
Every current browser supports this, but it only became Baseline on Feb 11, 2026. Use it as a progressive enhancement, or keep a fallback if you support older devices.
Example
Full syntax and examples are on MDN: Accept-Encoding#zstd.
Feature detection
There’s no simple runtime check for this feature; rely on the support table and test in your target browsers.
Documentation (MDN)
Specification
Usage share
Sub-features
Support for each part of the feature (2). The overall table above shows when the whole feature works.
| Sub-feature | Chrome | Edge | Firefox | Safari | Chrome Android | Firefox Android | Safari iOS |
|---|---|---|---|---|---|---|---|
| http.headers.Accept-Encoding.zstd | 123 | 123 | 126 | 26.3 | 123 | 126 | 26.3 |
| http.headers.Content-Encoding.zstd | 123 | 123 | 126 | 26.3 | 123 | 126 | 26.3 |