request-headers.md

Request Headers

Header	Description	Example Value
A-IM	Acceptable instance-manipulations for the request.	feed
Accept	Media type(s) that is/are acceptable for the response.	text/html
Accept-Charset	Character sets that are acceptable.	utf-8
Accept-Datetime	Acceptable version in time.	Thu, 31 May 2007 20:35:00 GMT
Accept-Encoding	List of acceptable encodings.	gzip, deflate
Accept-Language	List of acceptable human languages for response.	en-US
Access-Control-Request-Method	Initiates a request for cross-origin resource sharing with Origin.	GET
Access-Control-Request-Headers	same as above	origin, x-requested-with
Authorization	Authentication credentials for HTTP authentication.	Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ=
Cache-Control	Used to specify directives that must be obeyed by all caching mechanisms along the request-response chain.	no-cache
Connection	Control options for the current connection and list of hop-by-hop request fields. [HTTP/2]	keep-alive
Content-Length	The length of the request body in octets (8-bit bytes).	348
Content-MD5	A Base64-encoded binary MD5 sum of the content of the request body.	Q2hlY2sgSW50ZWdyaXR5IQ==
Content-Type	The Media type of the body of the request (used with POST and PUT requests).	application/x-www-form-urlencoded
Cookie	An HTTP cookie previously sent by the server with Set-Cookie.	$Version=1; Skin=new;
Date	The date and time (RFC 7231) at which the message was originated.	Tue, 15 Nov 1994 08:12:31 GMT
Expect	Indicates that particular server behaviors are required by the client.	100-continue
Forwarded	Disclose original information of a client connecting to a web server through an HTTP proxy.	for=192.0.2.60;proto=http;by=203.0.113.43
From	The email address of the user making the request.	user@example.com
Host	The domain name of the server (for virtual hosting), and the TCP port number (may be omitted if the port is the standard port for the service requested) on which the server is listening.	en.wikipedia.org:8080
HTTP2-Settings	A request that upgrades from HTTP/1.1 to HTTP/2 MUST include exactly one HTTP2-Setting header field. This one is a connection-specific header field that includes parameters that govern the HTTP/2 connection, provided in anticipation of the server accepting the request to upgrade.	token64
If-Match	Only perform the action if the client supplied entity matches the same entity on the server. This is mainly for methods like PUT to only update a resource if it has not been modified since the user last updated it.	"737060cd8c284d8af7ad3082f209582d"
If-Modified-Since	Allows a 304 Not Modified to be returned if content is unchanged.	Sat, 29 Oct 1994 19:43:31 GMT
If-None-Match	Allows a 304 Not Modified to be returned if content is unchanged.	"737060cd8c284d8af7ad3082f209582d"
If-Range	If the entity is unchanged, send me the part(s) that I am missing; otherwise, send me the entire new entity.	"737060cd8c284d8af7ad3082f209582d"
If-Unmodified-Since	Only send the response if the entity has not been modified since a specific time.	Sat, 29 Oct 1994 19:43:31 GMT
Max-Forwards	Limit the number of times the message can be forwarded through proxies or gateways.	10
Origin	Initiates a request for cross-origin resource sharing (asks server for Access-Control-* response fields).	http://www.example-social-network.com
Pragma	Implementation-specific fields that may have various effects anywhere along the request-response chain.	no-cache
Proxy-Authorization	Authorization credentials for connecting to a proxy.	Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==
Range	Request only part of an entity. Bytes are numbered from 0.	bytes=500-999
Referer [sic]	This is the address of the previous web page from which a link to the currently requested page was followed.	http://en.wikipedia.org/wiki/Main_Page
TE	The transfer encodings the user agent is willing to accept: the same values as for the response header field Transfer-Encoding can be used, plus the "trailers" value (related to the "chunked" transfer method) to notify the server it expects to receive additional fields in the trailer after the last, zero-sized, chunk. [HTTP/2: only trailers is supported]	trailers, deflate
Trailer	The Trailer general field value indicates that the given set of header fields is present in the trailer of a message encoded with chunked transfer coding.	Max-Forwards
Transfer-Encoding	The form of encoding used to safely transfer the entity to the user: chunked, compress, deflate, gzip, or identity. [HTTP/2]	chunked
User-Agent	The user agent string of the user agent.	Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20100101 Firefox/12.0
Upgrade	Ask the server to upgrade to another protocol. [HTTP/2]	h2c, HTTPS/1.3, IRC/6.9, RTA/x11, websocket
Via	Informs the server of proxies through which the request was sent.	1.0 fred, 1.1 example.com (Apache/1.1)
Warning	A general warning about possible problems with the entity body.	199 Miscellaneous warning

Common non-standard Request Fields

Header	Description	Example Value
Upgrade-Insecure-Requests	Tells a server which (presumably in the middle of a HTTP -> HTTPS migration) hosts mixed content that the client would prefer redirection to HTTPS and can handle Content-Security-Policy: upgrade-insecure-requests. [HTTP/2]	1
X-Requested-With	Mainly used to identify Ajax requests. Most JavaScript frameworks send this field with value of XMLHttpRequest.	XMLHttpRequest
DNT	Requests a web application to disable (1)/enable (0) their tracking of a user. (This is Mozilla's version of the X-Do-Not-Track header field).	1
X-Forwarded-For	A de facto standard for identifying the originating IP address of a client connecting to a web server through an HTTP proxy or load balancer. Superseded by Forwarded header.	129.78.138.66, 129.78.64.103
X-Forwarded-Host	A de facto standard for identifying the original host requested by the client in the Host HTTP request header, since the host name and/or port of the reverse proxy (load balancer) may differ from the origin server handling the request. Superseded by Forwarded header.	en.wikipedia.org:8080
X-Forwarded-Proto	A de facto standard for identifying the originating protocol of an HTTP request, since a reverse proxy (or a load balancer) may communicate with a web server using HTTP even if the request to the reverse proxy is HTTPS. An alternative form of the header (X-ProxyUser-Ip) is used by Google clients talking to Google servers. Superseded by Forwarded header.	https
Front-End-Https	Non-standard header field used by Microsoft applications and load-balancers.	on
X-Http-Method-Override	Requests a web application to override the method specified in the request (typically POST) with the method given in the header field (typically PUT or DELETE). This can be used when a user agent or firewall prevents PUT or DELETE methods from being sent directly (note that this is either a bug in the software component, which ought to be fixed, or an intentional configuration, in which case bypassing it may be the wrong thing to do).	DELETE
X-ATT-DeviceId	Allows easier parsing of the MakeModel/Firmware that is usually found in the User-Agent String of AT&T Devices.	GT-P7320/P7320XXLPG
X-Wap-Profile	Links to an XML file on the Internet with a full description and details about the device currently connecting.	http://wap.samsungmobile.com/uaprof/SGH-I777.xml
Proxy-Connection	Implemented as a misunderstanding of the HTTP specifications. Common because of mistakes in implementations of early HTTP versions. Has exactly the same functionality as standard Connection field.	keep-alive
X-UIDH	Server-side deep packet insertion of a unique ID identifying customers of Verizon Wireless; also known as "perma-cookie" or "supercookie"
X-Csrf-Token	Used to prevent cross-site request forgery. Alternative header names are: X-CSRFToken and X-XSRF-TOKEN.	i8XNjC4b8KVok4uw5RftR38Wgp2BFwql
X-Request-ID/X-Correlation-ID	Correlates HTTP requests between a client and server.	f058ebd6-02f7-4d3f-942e-904344e8cde5
Save-Data	The Save-Data client hint request header available in Chrome, Opera, and Yandex browsers lets developers deliver lighter, faster applications to users who opt-in to data saving mode in their browser.	on

Source

https://en.wikipedia.org/wiki/List_of_HTTP_header_fields