Our planned session comprises three parts. At first, we will give an introduction to JooMDD, a platform that can be used for model-driven development of Joomla extensions. In the second part we illustrate development scenarios which are possible with JooMDD. This includes the development of J4 components as well as the modernization of an existing J3 component to Joomla 4. In the last part of the session we will demonstrate the scenarios within a live demo.