Content Delivery Network – Definition

A geographically distributed network of servers that delivers web content to users based on their location for improved performance.

CDNs cache content at edge locations worldwide, reducing latency and improving page load times. They're essential for global e-commerce sites to ensure fast performance regardless of user location. The performance benefit of a CDN comes from physical proximity: a customer requesting a page from a server on another continent experiences meaningful network latency simply from the distance data has to travel, whereas a nearby edge node can serve cached content almost instantly. CDNs are most effective for content that doesn't change on every request — product images and largely static page content cache well, while highly dynamic or personalized content generally can't be cached the same way. Cache invalidation is the practical complexity that comes with CDN usage: when content changes, the CDN's cached copy needs to be purged or updated promptly, or customers in different locations may see stale content for a period after a change is made — which is why content platforms integrating with a CDN need reliable cache invalidation triggered automatically by publishing events, not manual purging as an afterthought.