A year ago I finished building a large distributed system to support an online game. We used a the most advanced tooling and patterns known at that time but we still didn't exactly get what we needed. [new paragraph] Habitat needed a similar large, distributed system of it's own: Builder. Builder is the first production application built with Habitat in mind. I will explore the development process of Builder, lessons learned along the way, and show you how Habitat helped us build and deploy a scalable, distributed hosted service.