Expires 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 HTTPExpiresresponse header contains the date/time after which the response is considered expired in the context ofHTTP caching.

The value0 is used to represent a date in the past, indicating the resource has already expired.

Note:If there is aCache-Control header with themax-age ors-maxage directive in the response, theExpires header is ignored.

Header type	Response header
CORS-safelisted response header	Yes

Syntax

http

Expires: <day-name>, <day> <month> <year> <hour>:<minute>:<second> GMT

<day-name>: One ofMon,Tue,Wed,Thu,Fri,Sat, orSun (case-sensitive).
<day>: 2 digit day number, e.g., "04" or "23".
<month>: One ofJan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec (case sensitive).
<year>: 4 digit year number, e.g., "1990" or "2016".
<hour>: 2 digit hour number, e.g., "09" or "23".
<minute>: 2 digit minute number, e.g., "04" or "59".
<second>: 2 digit second number, e.g., "04" or "59".
GMT: Greenwich Mean Time. HTTP dates are always expressed in GMT, never in local time.