Cookie header
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The HTTP Cookie request header contains stored HTTP cookies associated with the server (i.e., previously sent by the server with the Set-Cookie header or set in JavaScript using Document.cookie).
The Cookie header is optional and may be omitted if, for example, the browser's privacy settings block cookies.
| Header type | Request header |
|---|---|
| Forbidden request header | Yes |
Syntax
Cookie: <cookie-list>
Cookie: name=value
Cookie: name=value; name2=value2; name3=value3
Directives
-
A list of name-value pairs in the form of
<cookie-name>=<cookie-value>. Pairs in the list are separated by a semicolon and a space.
Examples
Sending cookies
Cookie: PHPSESSID=298zf09hf012fh2; csrftoken=u32t4o3tb3gg43; _gat=1
Cookies with the same name
Multiple cookies can have the same name if they were set with different Path or Domain attributes.
This includes the case where one cookie was set with a Domain attribute and the other without, even if they apply to the same host. If more than one matches a request, the browser can include all of them in the Cookie header.
Partitioned cookies are keyed on the top-level site as well, so cookies can have the same name if set by the same host in two different embedding contexts. See CHIPS.
For example, suppose separate responses from the same host set these cookies:
Set-Cookie: theme=light; Path=/
Set-Cookie: theme=dark; Path=/docs
A request to /docs can contain both of them:
Cookie: theme=dark; theme=light
The Cookie header does not include the cookies' attributes, and the cookie entries are unordered, so the server cannot determine their paths or domains from the header alone.
Specifications
| Specification |
|---|
| HTTP State Management Mechanism # cookie |