than to fetch the full state and calculate the diffs It's rarely a thing. Long polling request usually includes an increasing reference point like last-id or l

than to fetch the full state and calculate the diffs It's rarely a thing. Long polling request usually includes an increasing reference point like last-id or last-event-time, based on which the event source filters events or, if there is none, decides to block until they happen. It's still the same event stream, but with a little persistent counter on a client's side. The idea is that if a client encounters a data loss, it doesn't beg their server to reset some "delivered" flags from yesterday. Iow, webhooks are stateful, event streams are usually stateless.