CDN (Content Delivery Network)

A content delivery network is a distributed group of edge servers that receives requests in front of a website's origin server. An edge can return a cached copy of a public resource—such as an image, stylesheet, script, video, or page—or retrieve the response from the origin when the resource is missing, expired, private, or otherwise uncacheable. Shorter network paths, connection reuse, caching, compression, and optimized routing can reduce latency and origin load, but the result depends on the provider, configuration, content, and visitor location.

Why it matters: A CDN is infrastructure, not an automatic speed guarantee. Define cache rules and cache keys deliberately; use versioned asset URLs and appropriate Cache-Control headers; purge or revalidate changed files; and keep personalised, authenticated, or sensitive responses out of shared caches. Review cache-hit ratio, edge and origin timing, transfer size, errors, and real-user performance by region. A cache miss still reaches the origin, and an extra third-party connection or poor cache policy can add work. Confirm what your hosting plan enables instead of assuming every platform includes equivalent CDN coverage or behaviour.