A12 is an Enterprise Low Code Platform used to develop, integrate, maintain, and operate complex business applications in large-scale IT landscapes. One of its success stories is the German tax management system ELSTER. A12 combines a low-code approach enabling business experts to create application components without any programming knowledge with enterprise-grade custom software development and system integration. This talk gives an overview of what business experts achieve by pure modeling without code extensions in A12. Following the “data first” modeling paradigm, A12 modeling begins with defining the enterprise entities and their interrelationships in data models. Modelers realize the application logic by defining validation rules and computations via an integrated domain-specific language and workflows via BPMN models. UI models usually refer to A12 data models and establish connections between the fields of data models and UI ele¬ments. Instead of a what-you-see-is-what-you-get principle, the UI models describe the underlying structures of the user interface. Model interpreters (engines) of the A12 runtime platform execute the models. The resulting business application provides a rich feature set including localization, responsive design, themeability, and accessibility. Further development improves A12 and its modeling capability constantly, providing more and more (modeling) features to speed up the development of new projects.