CDN

A Content Delivery Network (CDN) caches your content on servers close to users, so that a request for an image, video segment, or API response is answered at the edge instead of at your origin. Cache hits reduce latency for users and load on your infrastructure.

CDNs work at multiple levels: static file caching, full-page caching, and increasingly dynamic acceleration where the edge terminates TLS and keeps a warm connection to your origin. Rules control TTLs, cache keys, and what happens when the edge must fetch from origin (including stale-while-revalidate behavior).

The pricing models differ sharply: most providers charge per gigabyte delivered, sometimes with regional rate cards, while some offer flat-rate or request-based pricing. Cache hit ratio is the metric to watch — a CDN with cheap list rates but a poor hit ratio costs more than an expensive one that actually answers at the edge.