A CDN is a network of servers distributed across different locations that store copies of a website's static files and deliver them to the visitor from the location closest to them. The benefit is greatest for visitors from distant countries, where distance alone adds measurable latency, and for websites with lots of images and videos. A second benefit is resilience under sudden load, for example during a campaign or a sale, since some requests never reach the origin server. Most solutions today also include protection against attacks and basic security functions. For a small website with a local audience, the benefit is small; for an e-shop expanding abroad, it is one of the first measures to take. After deployment, check that the cache is being refreshed correctly.
See also: Server response time, Expansion, Core Web Vitals.
