This talk shares practical lessons from building and scaling Temporal Cloud’s control plane on Temporal itself. Drawing from our experience operating a production-critical system that now handles billions of billable actions per month, we will explore how our architecture evolved over 5+ years as we ran into challenges around execution patterns, reliability, security, cross-namespace orchestration, and developer experience. Along the way, we will highlight the tradeoffs behind key design decisions, what broke as we grew, and the tooling and platform improvements that helped us operate more safely and effectively at scale.