In this paper, we present a framework for the automated design of integrated multi-domain systems. The platform allows the designer to set optimization problems according to a hierarchical decomposition strategy, define complex specification functions for each block at a given hierarchical level, follow the progress of optimization and finally view results. Encapsulation of design methodologies is simplified through access to a library of optimization algorithms. The framework is demonstrated through the co-synthesis of a high-speed CMOS photoreceiver front-end comprised of a PIN photodiode and a transimpedance amplifier.