Content Delivery Network Caching

content delivery network caching

Content delivery network caching is the practice of storing copies of web resources on servers distributed around the world so they can be delivered from a nearby location. These stored copies commonly include images, videos, scripts, and sometimes entire pages or API responses, and they allow many requests to be answered without contacting the origin server each time. Caching behavior is controlled by rules and headers that specify how long an item stays valid and when it should be refreshed, and cache hit rates show how often requests are served from the distributed copies instead of the origin. This matters because serving content from nearby caches reduces latency, makes pages load faster, and lowers the load and costs on the origin server, improving scalability and reliability. Cached resources can keep a site functional during origin outages, but overly long caching can lead to stale content, so developers must balance speed with freshness. Strategies like cache invalidation, versioned filenames, sensible cache-control headers, and monitoring of cache keys and time-to-live values help maintain correctness. When configured thoughtfully, caching is a foundational technique that makes online content quicker, more resilient, and easier to scale.