The NOUS Smart City Architecture (NSCA) is an extensible middleware designed to synchronize intelligent urban services across the edge–cloud continuum. By utilizing the lightweight MQTT protocol at the edge for low-latency communication among assets like vehicles and roadside units, and integrating the SIMPL-based Data Space Ecosystem in the cloud, NSCA ensures scalable data exchange and governance. These layers are seamlessly bridged by a flexible inter-broker connector that allows for efficient topic federation and minimal configuration for new service integration.