“What’s Facebook’s mobile architecture?” is a question we hear often. Instead of top-down MVC, MVW or MVVM, Facebook delegates the responsibility of choosing the right architectural patterns down to the engineers working on products. This episode's guests Yuan and Dustin pick up where Fabio left us in episode 28 and explain how the Product Foundation org builds abstractions that give engineers autonomy when they want and constraints for features to work cross-app when they need it.