Content Delivery Network

A Content Delivery Network (CDN) is a distributed network of servers that delivers web content from a location physically close to each user. When a visitor requests a page, the request is routed to a nearby edge server instead of the origin server. That edge server holds cached copies of static files such as images, stylesheets, scripts, and video segments. Shorter network distance means lower latency, so pages render faster while the origin handles far less traffic. Modern CDNs do more than caching. They terminate TLS, absorb denial-of-service traffic, compress responses, and run application code at the edge. Cloudflare, Akamai, Amazon CloudFront, and Fastly are the widely used providers, and platforms such as Vercel and Netlify build their hosting products on top of similar edge networks. A common pitfall is cache invalidation. If a deployment ships new assets but the CDN keeps serving old cached copies, users see a stale site, so teams put content hashes in filenames or purge the cache on every deploy. A CDN also cannot speed up responses that must be computed fresh for each user, which is where edge computing and server-side caching take over.