The Zstd accept-encoding header

Recently, you may have noticed a new value in the Accept-encoding headers sent by Chrome browsers. Instead of the usual gzip, deflate, br, you may have started to observe gzip, deflate, br, zstd.

What is the zstd encoding?

zstd stand for Zstandard, which is a fast lossless compression algorithm. This new compression algorithm will help browsers to load pages faster and use less bandwidth. On the server-side, it also helps to use less computational resources (CPU/power) on compression, resulting in reduced server costs.

Is it normal to see Chrome browsers sending zstd in the Accept-encoding header?

Yes, it is normal to see Chrome browser sending a gzip, deflate, br, zstd encoding value starting from Chrome 123 as this is when it was made available.

Note that it's possible for older Google Chrome browser versions to have this value since you could activate it using the enable-zstd-content-encoding flag.

Will zstd compression be available in other browsers?

Both Firefox and Safari gave a positive feedback on the implementation of this new compression algorithm. However, they didn’t communicate about a release date.