When it comes to the implementation of mobile apps with web technologies, progressive web apps are a good alternative to solutions like React Native or Ionc. If you are working with PWAs you will face a range of new and old problems. The biggest problem is, that you have to rethink the way you implement your application. Not having a network connection is not an exception but a normal part of your application. This affects the way you log in to your application, store information and synchronize data between client and server. In this talk you will see practical examples of these solutions and learn about the advantages and disadvantages.