National promo day meant five times the usual loan applications in one hour. We'd seen what happens when you're not ready — slow responses, timeouts, angry customers. So weeks before, we load-tested everything, tuned caches, and indexed the database queries that would get hammered hardest.
When the surge hit, p95 latency barely budged. The celebration was quiet — just Slack emojis and early bedtimes. My favourite kind of victory. The best infrastructure work is the kind nobody notices, because nothing went wrong.