In this paper, we describe a way to use UML diagrams for configuring web-application’s behavior. That is, using the configuration will determine the behavior of the system, the transitions between the screens, as well as the business logic of application. We examine and compare various UML diagrams for their possible features. A web framework for ASP.NET Core is developed, which uses the UML diagram to form a configuration in the XML or JSON file formats. Configuration will determine the behavior of the system. In addition, we describe further steps in using and developing the web-framework.