Expires header - HTTP | MDN (original) (raw)
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The HTTP Expires response header contains the date/time after which the response is considered expired in the context of HTTP caching.
The value 0 is used to represent a date in the past, indicating the resource has already expired.
**Note:**If there is a Cache-Control header with the max-age or s-maxage directive in the response, the Expires header is ignored.
| Header type | Response header |
|---|---|
| Forbidden request header | No |
| CORS-safelisted response header | Yes |
Syntax
Expires: <day-name>, <day> <month> <year> <hour>:<minute>:<second> GMT
Directives
One of Mon, Tue, Wed, Thu, Fri, Sat, or Sun (case-sensitive).
2 digit day number, e.g., "04" or "23".
One of Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec (case sensitive).
4 digit year number, e.g., "1990" or "2016".
2 digit hour number, e.g., "09" or "23".
2 digit minute number, e.g., "04" or "59".
2 digit second number, e.g., "04" or "59".
Greenwich Mean Time. HTTP dates are always expressed in GMT, never in local time.
Examples
Expires: Wed, 21 Oct 2015 07:28:00 GMT
Specifications
| Specification |
|---|
| HTTP Caching # field.expires |