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HTTP Header Reference
Every common request and response header with its direction, its status and an example value, filterable as you type.
Search HTTP headers
Showing 0 headers
How to use the HTTP Header Reference
- Type part of a header name, an example value or a keyword in the search box.
- Filter the list by direction or by standard and extension headers.
- Read the example and the notes, then copy the header name into your code.
Features
- Request, response and bidirectional headers
- Standard and common extension fields marked
- Example value and short notes for each entry
- Search and direction filters
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Frequently Asked Questions
Common questions about the free online http header reference.
A header is a field sent with a request or response that carries metadata such as the content
type, caching rules or authentication.
Request headers describe what the client wants, while response headers describe the result
and how it may be cached or stored.
Headers defined by the HTTP specification, such as Accept, Cache-Control and ETag, are marked
as standard in the table.
They are widely used fields that are not part of the core specification, such as
X-Forwarded-For or X-Request-Id.
It tells caches how long a response may be reused and under which conditions, replacing the
older expiry only headers.
It carries credentials, so it must only be sent over HTTPS and must never be written to logs
or shared with third parties.
Access-Control headers let a browser decide whether a page from another origin may read the
response of a request.
Type any part of a header name, a direction, an example value or a note in the search box and
the table filters as you type.
Yes. It is free to use and keeps working offline once the page has loaded in your browser.
Last updated: October 10, 2026