With the introduction of Progressive Web Apps and browser APIs such as persistent storage, payments, geolocation, and push notifications, it is now possible to build fully-featured mobile apps on the web platform. One important aspect of Progressive Web Apps is the concept of building your app to be Offline First. With an Offline First approach, you design your app for the most resource-constrained environment first. This approach provides a consistent user experience whether the user's device has no connectivity, limited connectivity, or great connectivity. One of the biggest benefits of Offline First apps is that they can be very fast, as they provide zero-latency access to content and data stored directly on the device.