Offline first web applications provide the ability to design web applications for offline access by employing caching and updating mechanisms. The implementation requires a flag in the DOM to check whether the accessing device is offline or online, accessing local storage when offline, and synchronising data when online. All the major browsers now support an offline mode, which bootstraps the process of downloading and caching the resources such as HTML, CSS, JavaScript, images and other kinds of resources. There are some tools which help simplify offline first implementation such as Hoodie, and CouchDB also offers ability to work with a locally deployed application on a local data storage.