Explore offline-first application development in this JSConf Iceland 2018 talk. Learn how to engineer robust web applications that function seamlessly both online and offline. Discover techniques for storing state, tracking mutations, and synchronizing data using a git-inspired approach. Gain insights into creating intuitive user experiences that clearly represent data in transition. Delve into topics such as App Shell architecture, Web Standards, backend considerations, and the implementation of Orbit JS. Understand the benefits of optimistic updates and deterministic change tracking for enhanced online performance. Master the art of building applications with "online superpowers" that provide superior user experiences in both connected and disconnected scenarios.