Designing embedded systems increasingly demands coping with heterogeneous systems, involving different models of computation, communication, and execution, on different levels of abstraction and different time scales. The component model BIP (Behavior, Interaction model, Priority) has been designed to support the construction of heterogeneous reactive systems. It enables heterogeneous modeling by separating the notions of behavior, interaction model, and execution model. We present here the design tool Prometheus, which implements the BIP component model, along with a set of algorithms for compositional verification. The use of the component framework is illustrated with two case studies involving different models of computation and communication.