content-deliverylisted

# Content Delivery Push bytes to the network edge so requests terminate close to the user and never reach the origin. A CDN is the outermost cache layer of a system: get it right and most static/media traffic and a chunk of latency vanish before they hit your servers; get it wrong and you serve stale assets, leak origin load, or pay egress twice. ## When to reach for this The same files (images, video, JS/CSS bundles, downloads, fonts) are read repeatedly by a geographically spread audience; the origin or its bandwidth is the bottleneck for static reads; or cross-region latency on first byte hurts (a cross-continent round trip is ~100 ms — see `back-of-the-envelope`). A CDN buys latency *and* origin offload at once. ## When NOT to Highly personalized, per-request dynamic responses with no cacheable shape (a CDN adds a hop and caches nothing). Tiny single-region audiences where the origin already serves reads comfortably (YAGNI — a CDN is another vendor, another bill, another invalidation problem). Strictly fresh data that cannot tolerate any staleness window — that belongs at the origin or behind `consistency-coordination`, not a TTL-based edge. Naming a CDN before a number shows static reads or geography is the problem is a red flag. ## Clarify first - **Content mix** — what fraction is cacheable static/media vs uncacheable dynamic/personalized? (Only the cacheable part benefits.) - **Update cadence & staleness budget** — how often do assets change, and how stale may