Why I Made WebSocket Delivery the Disposable Part of the Tracking System

The uncomfortable failure is not a carrier outage. That one is loud. The polling loop logs it, retries it, and moves on. The failure I had to design around is quieter: the gateway receives a real carrier update, writes it to the database, then Redis is down at the exact moment the WebSocket fanout should happen. The client misses the live push. The shipment state is still correct. The event timeline is still correct. But the thing the user was watching in real time never moves. That sounds like