The ongoing growth of city populations has brought new challenges and increased complexity to everyday city life. In response, numerous cities are making efforts to adopt new information technologies to become more efficient and transform themselves into smart cities. A large body of research has underlined that the success of these smart city initiatives depends on putting citizens at the center of the design process. In contrast to the techno-centric viewapplied in the past, citizen-centric approaches focus on prioritizing the needs of citizens over technology and aim at involving them directly in the development of smart city services. In this article, we describe this involvement as citizen development by introducing a model-based architecture that enables citizens to develop smart city services in a low-code fashion. Consequently, we focus on citizen developers, a group of citizens engaged with the technological development of services. Furthermore, the conceptualization of a citizen development architecture is discussed, as well as the ways citizens can interact with it. An important pillar in this approach are citizen workshops, which aim at stimulating innovative ideas and collaboration among stakeholders by using design thinking methodology. Our approach empowers citizens to become active producers within the smart city ecosystem, leading to more inclusive and citizen-centric smart cities.