HTTP Headers

Updated 17 Sep 2026

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What it is
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  named fields carrying metadata or control information about a request, response, representation, or connection
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Syntax
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  HTTP/1.1 commonly displays a field as Name: value
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  value syntax depends on the field; not every header follows one universal parameter grammar
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Request examples
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  Host — target authority in HTTP/1.1
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  Accept — acceptable response media types
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  Accept-Language — language preferences
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  Accept-Encoding — acceptable content codings such as gzip
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  User-Agent — client identification
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  Referer — referring URL, subject to policy and omission
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  Authorization — authentication credentials
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  Cookie — stored cookie values
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Response examples
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  Content-Type — the returned content’s media type
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  Content-Encoding — coding applied to the representation
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  Content-Length — length in bytes as defined for that message
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  Location — a destination or resource location
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Distinguish from
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  Accept states client preferences; Content-Type describes the content actually sent
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Related
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  HTTP Content Negotiation
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  Cache-Control

Linked references 2