Explore the architectural evolution of a global identity platform through seven years of Ruby on Rails development at scale. Learn from real-world experiences transitioning from Google App Engine to a globally distributed, multi-cluster Kubernetes deployment while maintaining system simplicity. Discover the critical architectural turning points, trade-offs, and mistakes encountered when scaling Rails applications to serve businesses worldwide. Examine how complexity can unexpectedly emerge in growing systems and understand why prioritizing simplicity becomes essential for successful scaling without overwhelming technical debt. Gain battle-tested insights on system design principles, strategic technical decision-making, and building sustainable Rails applications for long-term growth, whether you're launching new projects or managing existing large-scale deployments.