How do engineers at Facebook build products with React Native? We'll walk you through building a simple screen in the Facebook app with React Native on both platforms, covering some GraphQL in the process. We'll discuss the collaboration between engineers and designers. We'll also cover A/B testing which is a crucial part of shipping most code at Facebook. The talk has practical examples taken from a project Martin worked on. This talk was presented at React Native EU 2017, September 6-7, Wroclaw, Poland.