Absorbed a 4x launch spike with autoscaling
A third-party dependency in the middle of a critical path went down and took us with it, because we had quietly trusted it never would. I made the system survive its dependencies — timeouts, fallbacks, and circuit breakers that turned an outage into a degradation nobody outside even noticed.
Load-tested to the real ceiling and tuned autoscaling; a 4x traffic spike scaled cleanly with headroom to spare.