AcceptcontentDescribes the media types the client can process.
HTTP Headers Reference
Filter common HTTP headers, read their direction and purpose, and copy a header name for documentation or implementation.
Search by name, category, or purpose. Everything stays in this browser.
Accept-EncodingcontentLists content codings the client can decode.
AuthorizationsecurityCarries credentials for the requested resource.
Cache-ControlcachingControls caching rules for browsers and intermediaries.
Content-LengthcontentGives the size of the message body in bytes.
Content-TypecontentDescribes the media type and optional character set of the body.
CookiecookiesSends stored cookies to the server for the current domain.
ETagconditionalIdentifies a specific representation for cache validation.
HostgeneralIdentifies the host and optional port targeted by the request.
If-None-MatchconditionalMakes a request conditional on an ETag not matching.
If-Modified-SinceconditionalRequests a response only when a representation changed after a date.
LocationgeneralProvides a URL for redirects or a newly created resource.
OrigincorsIdentifies the origin that initiated a request.
ReferergeneralIdentifies the address of the page that made the request.
Set-CookiecookiesAsks the browser to store a cookie.
Strict-Transport-SecuritysecurityTells browsers to use HTTPS for a host for a period of time.
User-AgentgeneralIdentifies the client software making the request.
VarycachingLists request headers that affect representation selection.
WWW-AuthenticatesecurityDefines an authentication challenge for a protected resource.
X-Content-Type-OptionssecurityPrevents MIME sniffing when set to nosniff.
No headers match these filters.
A QUICK WALKTHROUGH
How to use this tool
- Search by a header name or purpose, or choose a direction and category.
- Review the header description and whether it belongs to requests, responses, or both.
- Copy the header name for your documentation or implementation.
A focused HTTP header reference
The list covers widely used standard, CORS, security, caching, content, and conditional request headers. It is a practical lookup, not a replacement for the specification.
Direction matters
Some headers are sent by clients, some by servers, and some are meaningful in both directions. The direction filter helps avoid copying a response-only header into a request.
Runs locally
The reference data is bundled with this page. Searching, filtering, and copying do not send your query or selected header to a server.
GOOD TO KNOW
Common questions
Does this include every registered HTTP header?
No. It focuses on common headers useful in everyday web development and includes a few established security and CORS headers.
Can I use every header in both directions?
No. Check the direction label. A request header is sent by a client, a response header by a server, and a general header may apply to either message.
Does searching contact a server?
No. The data and all interactions run locally in your browser.