HTTP headers

Cache-Control HTTP Header Meaning

Cache-Control sets caching rules for browsers and shared caches.

Meaning

The header defines how long a response can be reused and when it must be revalidated or stored.

Servers send it on responses; clients can also send request directives for cache behavior.

Check max-age, shared-cache directives, no-store rules, and whether the response can safely be cached.

Cache-Control: max-age=3600, stale-while-revalidate=60

max-age: max-age=<seconds>Caches can reuse the response for this many seconds before revalidating.
s-maxage: s-maxage=<seconds>Shared caches use this value instead of max-age.
no-cache: Caches may store the response, but must revalidate before reuse.
no-store: Caches should not store the request or response.
private: Only a private browser cache may store the response.
public: Shared caches may store the response even when it would otherwise be restricted.
must-revalidate: Once stale, caches must revalidate before reuse.
stale-while-revalidate: stale-while-revalidate=<seconds>Caches may serve stale content briefly while refreshing it in the background.
stale-if-error: stale-if-error=<seconds>Caches may serve stale content when revalidation or origin fetch fails.