Providing and maintaining lightweight graphical user interfaces for embedded devices is becoming an increasing burden. In particular, the commonly applied Web-interfaces usually require continuous maintenance during the product life cycle to keep up with changes in browser clients. Furthermore, in many application scenarios, like building automation, smart homes or smart factories, large numbers of embedded devices must be controlled and maintained through multiple remote user terminals that provide composite user interfaces for multiple devices (e.g., all actors in a hotel room). In this paper, we present an architecture for lightweight graphical user interfaces for embedded devices in which all presentation aspects, such as control layout and appearance, are completely defined and implemented by the clients. The embedded device only implements the presentation-independent core functionality of UI controls in terms of state changes in response to client events. As a result, different client implementations can directly connect to these controls and provide individual implementations of the complete presentation, including the capability to combine UI elements from various devices into a single user interface.