For most of the web, poor network connectivity destroys the user experience. We can do better. In this session we'll take an online-only site and turn it into a fully network-resilient, offline-first installable progressive web app, and this won't involve rebuilding from scratch; it'll be done in small iterations, with each step improving the user experience whether they're offline, online, or anything in between. The session will cover ServiceWorker, web manifests, add-to-homescreen banners, IndexedDB and BackgroundSync APIs.