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Expires header

files/en-us/web/http/reference/headers/expires/index.md

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The HTTP Expires {{Glossary("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 {{HTTPHeader("Cache-Control")}} header with the max-age or s-maxage directive in the response, the Expires header is ignored.

<table class="properties"> <tbody> <tr> <th scope="row">Header type</th> <td>{{Glossary("Response header")}}</td> </tr> <tr> <th scope="row"> {{Glossary("CORS-safelisted response header")}} </th> <td>Yes</td> </tr> </tbody> </table>

Syntax

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

Directives

  • <day-name>
    • : One of Mon, Tue, Wed, Thu, Fri, Sat, or Sun (case-sensitive).
  • <day>
    • : 2 digit day number, e.g., "04" or "23".
  • <month>
    • : One of Jan, 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.

Examples

http
Expires: Wed, 21 Oct 2015 07:28:00 GMT

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

  • HTTP caching guide
  • {{HTTPHeader("Cache-Control")}}
  • {{HTTPHeader("Age")}}