Cache-Control.
also: Cache-Control header · max-age · s-maxage · no-store · no-cacheThe HTTP header telling browsers and CDNs whether and how long to cache a response: max-age, private, public, no-store, no-cache.
the two-minute refresher
- public, max-age=86400: anyone (browser, CDN) may cache for a day.
- private: only the browser may cache, never a shared CDN.
- no-cache: store but revalidate before use. no-store: don't cache at all.
- max-age=31536000, immutable for versioned static assets.