For 18 months, our API gateway’s p99 reverse proxy latency hovered at 210ms, costing us $18k/month in wasted compute and driving a 12% churn rate among high-frequency API consumers. We replaced Apache 2.4.57 with Nginx 1.25.3, and cut that latency by 25% to 157ms, with zero unplanned downtime. Here’s exactly how we did it, with benchmarks, code,...