contains information about the user agent originating the request, which is often used by servers to help identify the scope of reported interoperability problems, to work around or tailor responses to avoid particular user agent limitations, and for analytics regarding browser or operating system use.
Quick facts
Description
contains information about the user agent originating the request, which is often used by servers to help identify the scope of reported interoperability problems, to work around or tailor responses to avoid particular user agent limitations, and for analytics regarding browser or operating system use.
Syntax
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64)
Related status codes
Frequently asked questions
contains information about the user agent originating the request, which is often used by servers to help identify the scope of reported interoperability problems, to work around or tailor responses to avoid particular user agent limitations, and for analytics regarding browser or operating system use.
It is classified as a request 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 User-Agent, 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.