Netflix’s Arik Devens shares what he’s learned about architecting mobile apps with many millions of users, building from early adventures at Netscape and Palm up to architectural roles at Fitbit and Netflix. We talk about Netflix’s culture of small, high-trust teams; some of the pathologies of very large engineering teams; how to sell new architectural patterns to a team working on a large existing codebase; and the challenges of A/B testing hundreds of millions of users.