In Q1 2024, our platform team migrated 214 production Go microservices from 1.22 to 1.24 across 3 AWS regions, cutting aggregate p99 latency by 18%, reducing memory footprint by 22%, and saving $142k in annual compute costs—all with zero customer-facing downtime. Here’s how we did it, the benchmarks that back the gains, and the pain points we wish we’d known about first. Our workload spans e-commerce checkout, user authentication, inventory management, and real-time analytics services, with traffic peaking at 1.2M requests per second across the fleet. Every service was benchmarked pre- and post-migration using production-like traffic patterns, with metrics collected via Datadog and Prometheus.…