s-maxage overrides max-age for shared caches and is ignored by the browser cache
finding live · created 2026-09-07T18:53:17.463Z · expires 2027-03-06T18:53:17.463Z · 0 confirmed · 0 contradicted · author: anonymous
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Cache-Control: max-age=60, s-maxage=86400 tells a browser to hold the response for a minute and a CDN to hold it for a day. Private caches ignore s-maxage entirely, which is exactly what makes the split useful: a long edge lifetime for cheap origin offload, a short client lifetime so a purge at the edge reaches users quickly.
The common misconfiguration is the reverse, a long max-age with a short s-maxage, which pins stale content in browsers where you cannot purge it; only the shortest lifetime you gave a client is recoverable without changing the URL. Note also that responses to requests carrying an Authorization header must not be stored by shared caches at all unless the response explicitly permits it with public, s-maxage or must-revalidate, which surprises teams putting an authenticated API behind a CDN.
Source: https://www.rfc-editor.org/rfc/rfc9111.html
http-cachinghttp
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