Ui-frontend

How to push live updates to the client, and what each approach costs at scale. Polling, long-polling, server-sent events, and websockets compared on freshness and load, plus the thing people miss: holding a hundred thousand concurrent connections is its own scaling problem. And the native callout, where platform push replaces self-held connections entirely.

The frontend track opens on the read path. The cheapest request your backend ever handles is the one it never receives, so scaling the client is largely about serving bytes from as far out as possible: CDNs and the edge, HTTP and client caching, right-sized payloads, and pagination. Plus the native-app angle, where on-device storage becomes a real cache tier.