Presentation taken from Future of Web Apps Boston (http://futureofwebapps.com/boston-2014) In this talk, Steve will build a system from scratch for cross-device data synchronization in JavaScript. Through demos, he will explore all the things you're probably not thinking about when rolling your own sync engine, like offline caching, change notification, and conflict resolution. Drawing on his experience from Dropbox, Steve will discuss the thorny challenges around sync and how to solve them.