topic Registered
Verified 2026-09-19 · registry updated 2025-10-02

HTTP registry: zstd

A stream of bytes compressed using the Zstandard protocol with a Window_Size of not more than 8 MB.

HTTP parameter values extend negotiation, framing, preferences, range handling, or other protocol components. zstd is registered in HTTP Content Coding Registry. Defining reference: rfc9659.

httpregistryhttp-parameterscontent-coding

Identifier (http)

zstd

A stream of bytes compressed using the Zstandard protocol with a Window_Size of not more than 8 MB.

Interpret parameters only in the context that defines them; unknown parameters must not silently change security or framing behavior.

This registry value is currently marked active by IANA. Follow the defining specification before sending, accepting, or proxying it.

IANA registry: http-parameters/content-coding

Registry reference: rfc9659

Permalink: https://merginit.com/reference/http/registry/http-parameters/content-coding/zstd-119