Proxies and CDNs

A CDN, or content delivery network, is a fleet of caching servers spread around the world that keep copies of your site’s files close to your users. When someone in Tokyo requests an image, a nearby edge server answers from its cache; only on a miss does it fetch from your origin server and keep a copy for next time. That cuts latency, because the data travels a shorter distance, and takes most of the load off your own servers. A CDN is a kind of reverse proxy: a server that sits in front of your servers and answers on their behalf, as opposed to a forward proxy, which acts on behalf of clients.