Web apps are considered to work online only. When the Internet connection drops, the app usually stops functioning. Although in such situations we cannot enable the whole functionality, we can still let our users continue their work and thus give them good user experience. In this talk I will share design principles and implementation strategies to deliver better user experience with our apps. First, we need to rethink the traditional request-response model when designing web apps. Next, we should think about how to apply caching – which data to cache, when to do it, for how long and which mechanism to use. HTML5 has come with great caching mechanisms, but their status changes rapidly – some have been deprecated, while new ones have emerged.