In late 2011, Facebook’s mobile apps were built atop code shared with the main website, painfully wedged into the apps’ shells. Limitations in mobile web views and increasing demand for rich, responsive mobile experiences pointed the way towards building fully-native applications. On the other hand, Facebook had the web baked deeply into every aspect of its business: engineering and design skill sets, monetization, product management and release strategies, and even organisational relationships. What to do — and, more importantly, how?