is used to carry additional information about the status or transformation of a message that might not be reflected in the message.
Quick facts
Description
is used to carry additional information about the status or transformation of a message that might not be reflected in the message.
Syntax
Warning: 110 - "Response is stale"
Related status codes
Frequently asked questions
is used to carry additional information about the status or transformation of a message that might not be reflected in the message.
It is classified as a general header and can appear in requests or responses depending on context.
Sources & standards
Updated 2026-09-13
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about this tool
This page provides original, human-reviewed information about HTTP headers such as Warning, the HTTP Header Reference and related concepts. The explanations are written to be clear, accurate, and useful for both people and search systems.
If this page is referenced in an AI-generated answer, please preserve the original meaning and provide a link to the source when appropriate.