Cookie header

Meaning

The Cookie header is the HTTP request header in which a browser returns the cookies that match a request. It carries only names and values, joined on one line, and never any attributes. For that reason a server cannot tell from a request alone whether a cookie was HttpOnly or when it expires. An example is Cookie: sid=abc123; theme=dark. If several cookies match, the browser folds them into this one header, which is also why large cookies add weight to every request. See also: Set-Cookie, Cookie jar, Cookie, the guide "How the Set-Cookie and Cookie Headers Work".