This chapter describes the basic structure of a SDACK web application. As any typical web application it is built with a client-server archictecture. That means it has a server part that executes the process (or business) logic and a client part that consists of the user interface, running in a web browser. The good news is that by using SDACK a developer can concentrate on the server code. Apart from some bootstrap code the user interface is mostly generated automatically by the framework from process parameters.