Back in 2012, a team at Intel started working on a green-field project to build a next-generation TV service from the ground up - everything from the silicon to the service platform. From the very beginning the platform was built using Scala and functional programming idioms. The entire team was acquired by Verizon in early 2014 and we continue our work on that very same service platform. This experience report highlights how we grew our team from a small handful of engineers doing functional programming to a well over a hundred engineers using Scala every single day. This session also describes some of the technical benefits and pitfalls our team encountered during the process of building a large green-field system with Scala - where most of the engineering staff were new to functional programming - and how we went about edifying that large team on pure functional programming. Finally, we'll cover some of the ways packaging functional APIs can bridge the skills gap in large teams and ease the transition to FP whilst still allowing teams to ship operational systems.