Cache-Control: s-maxage

Overrides max-age for shared caches such as CDNs and proxies.

s-maxage lets a CDN cache for a long time while browsers revalidate sooner. Browsers ignore s-maxage entirely.

httpcacheheaderdirectivecdn

Reference (http)

Cache-Control: max-age=60, s-maxage=86400

s-maxage lets a CDN cache for a long time while browsers revalidate sooner. Browsers ignore s-maxage entirely.

Common mistakes

Assuming browsers honor s-maxage or forgetting that it also marks the response public-shared-cacheable.

Sources