A method in a user end station for interactive editing of one or more user interface, Ul, components of a running instance of a web application, comprising: acquiring a UI definition file that defines the web application including its structure, behavior, and appearance, wherein the UI definition file is configured for dynamic generation of application code representing a set of one or more UI components to be presented within the web application, the application code comprising at least one of HyperText Markup Language, HTML, and Cascading Style Sheets, CSS; initializing a UI of the web application using the UI definition file and a set of component definition files, the set of component definition files including code for implementing the set of one or more UI components indicated in the UI definition file, wherein the web application is dynamically generated at runtime under control of the UI definition file, and wherein initializing the UI of the web application using the UI definition file and the set of component definition files includes dynamically generating the application code representing the set of one or more UI components; dynamically loading into the running instance of the web application on the user end station an interactive editor that allows editing of one or more of the set of the one or more UI components of the running instance of the web application; responsive to receiving a user selection of a visual representation of a component in the running instance of the web application, determining a first Document Object Model, DOM, element of the web application; determining a first UI component that corresponds to the selected first DOM element; determining, from the UI definition file, a first set of one or more parameters defining the determined first UI component; displaying a value editor that is configured to display for at least one of the first set of one or more parameters a first value and allows for that first value to be modified to change a behavior of the first UI component; receiving a modification of at least the first value of the at least one of the first set of one or more parameters to change the behavior of the first UI component; and updating the running instance of the web application to reflect the modified first value by modifying the UI definition file with the modified first value of the at least one of the first set of one or more parameters defining the determined first Ul component and dynamically regenerating the running instance of the web application under control of the modified UI definition file and the set of component definition files to regenerate the first UI component to change the behavior of the first UI component based on the modified first value of the at least one of the first set of one or more parameters defining the first UI component. acquiring a UI definition file that defines the web application including its structure, behavior, and appearance, wherein the UI definition file is configured for dynamic generation of application code representing a set of one or more UI components to be presented within the web application, the application code comprising at least one of HyperText Markup Language, HTML, and Cascading Style Sheets, CSS; initializing a UI of the web application using the UI definition file and a set of component definition files, the set of component definition files including code for implementing the set of one or more UI components indicated in the UI definition file, wherein the web application is dynamically generated at runtime under control of the UI definition file, and wherein initializing the UI of the web application using the UI definition file and the set of component definition files includes dynamically generating the application code representing the set of one or more UI components; dynamically loading into the running instance of the web application on the user end station an interactive editor that allows editing of one or more of the set of the one or more UI components of the running instance of the web application; responsive to receiving a user selection of a visual representation of a component in the running instance of the web application, determining a first Document Object Model, DOM, element of the web application; determining a first UI component that corresponds to the selected first DOM element; determining, from the UI definition file, a first set of one or more parameters defining the determined first UI component; displaying a value editor that is configured to display for at least one of the first set of one or more parameters a first value and allows for that first value to be modified to change a behavior of the first UI component; receiving a modification of at least the first value of the at least one of the first set of one or more parameters to change the behavior of the first UI component; and updating the running instance of the web application to reflect the modified first value by modifying the UI definition file with the modified first value of the at least one of the first set of one or more parameters defining the determined first Ul component and dynamically regenerating the running instance of the web application under control of the modified UI definition file and the set of component definition files to regenerate the first UI component to change the behavior of the first UI component based on the modified first value of the at least one of the first set of one or more parameters defining the first UI component.