Compression Dictionary Transport
type: TechArticle
description: Use a previously served response, or a dedicated dictionary, as a Brotli/Zstandard dictionary so updated assets compress to a fraction of their size. Pure progressive enhancement over ordinary compression.
language: en
is part of: Web Specification Studio
author: Web Specification Studio
publisher: Web Specification Studio
license: https://creativecommons.org/licenses/by/4.0/
date modified: 2026-06-10T00:00:00.000Z
citation: RFC 9842 — Compression Dictionary Transport
  type: CreativeWork
  publisher: IETF
citation: MDN — Compression Dictionary Transport
  type: CreativeWork
  publisher: MDN
citation: MDN — Use-As-Dictionary
  type: CreativeWork
  publisher: MDN

Web Specification Studio
type: WebSite

Web Specification Studio
type: Organization

breadcrumb
type: BreadcrumbList
item list element: Home
  type: ListItem
  position: 1
  item: https://webspecification.com/
item list element: Spec
  type: ListItem
  position: 2
  item: https://webspecification.com/spec/
item list element: Performance
  type: ListItem
  position: 3
  item: https://webspecification.com/spec/performance/
item list element: Compression Dictionary Transport
  type: ListItem
  position: 4
  item: https://webspecification.com/spec/performance/compression-dictionary-transport/