SaaS · Logistics
A logistics SaaS hit a wall at 200 concurrent users — WebSocket connections were pinned to a single Node instance with no fanout. We rebuilt the realtime layer on Redis pub/sub with sticky sessions behind Hetzner load balancers, added backpressure, and shipped weekly under load. They now run 4,000 concurrent users on the same infra spend.
We reply to every email within 48 hours. Call or async, whichever you prefer.