Caching · Response header
Expires
Legacy: an absolute HTTP date when the response becomes stale.
What is Expires?
Expires provides an absolute date-time after which the response is considered stale. Superseded by Cache-Control: max-age, but still used as a fallback for very old caches.
Typical usage
Prefer Cache-Control: max-age. Only set Expires for legacy compatibility.
Examples
Expires: Wed, 21 Oct 2025 07:28:00 GMTCommon gotchas
If both Expires and Cache-Control: max-age are present, max-age wins. Server clocks drifting from client clocks make absolute Expires unreliable.
Specification
RFC 9111 §5.3
Related headers
Cache-Control
Directives that control caching behavior.
Date
When the response was generated.
ETag
A version identifier for the resource — the backbone of conditional GETs.
Age
How many seconds the response has been in a shared cache.
Vary
Which request headers cause different cached variants of the response.