cachingkontroll

Cachingkontroll, commonly known as Cache-Control in HTTP, is a mechanism used to govern how responses are cached by browsers, intermediary caches, and content delivery networks. Its purpose is to improve performance by serving resources from a cache when appropriate while ensuring content stays fresh and accurate. Cachingkontroll can be specified by the server in response headers and, less commonly, can be influenced by a client in request headers to steer caching behavior.

The header defines directives that control cacheability, freshness, and revalidation. Core directives include public, private, no-cache, no-store, max-age, and s-maxage. Public allows any cache to store the resource, while private restricts caching to a single user. No-store prevents caching altogether, and no-cache requires caches to revalidate with the origin server before serving a stale copy. Max-age sets the supported lifetime in seconds; s-maxage applies to shared caches like CDNs and can override max-age for those caches. Other useful directives include must-revalidate, proxy-revalidate, and immutable, which signal revalidation requirements and resource stability.

Cachingkontroll works together with related headers such as Expires, ETag, and Last-Modified, which enable validation and conditional requests. Real-world usage often combines Cache-Control with versioned URLs or fingerprinted assets to ensure updates propagate promptly while minimizing redundant transfers. Careful configuration balances performance with data freshness and privacy, especially for dynamic or user-specific content.