RFC 9211 · PROPOSED STANDARD · 2022
SUN · 14 JUN 2026
The Cache-Status HTTP Response Header Field
Overview
RFC 9211, “The Cache-Status HTTP Response Header Field”, is a Proposed Standard document published in June 2022 by M. Nottingham. The canonical text is published by the RFC Editor.
Abstract
To aid debugging, HTTP caches often append header fields to a response, explaining how they handled the request in an ad hoc manner. This specification defines a standard mechanism to do so that is aligned with HTTP's caching model.
What “Proposed Standard” means
An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.
Read this RFC
The canonical text of RFC 9211 is hosted at rfc-editor.org. Available in HTML,TXT,PDF,XML.
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- RFC 9209 The Proxy-Status HTTP Response Header Field
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- RFC 9214 OSPFv3 Code Point for MPLS LSP Ping
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- RFC 9215 Using GOST R 34.10-2012 and GOST R 34.11-2012 Algorithms with the Internet X.509 Public Key Infrastructure