The Robotics Service Bus (RSB) is a message-oriented, event-driven middleware aiming at scalable integration of robotics systems in diverse environments. Being fundamentally a bus architecture, RSB structures heterogeneous systems of service providers and consumers using broadcast communication over a hierarchy of logically unified channels instead of a large number of point-to-point connections. Nevertheless RSB comes with a collection of communication patterns and other tools for structuring communication, but does not require a particular functional or decomposition style.