The rapidly expanding field of Internet of Things (IoT) has necessitated the development of effective and efficient systems for handling the vast quantities of data that are generated. However, the inherent diversity and complexity of IoT environments, coupled with the large volume of data, pose significant challenges to achieving interoperability and efficient data exchange. ComDeX, is a novel approach designed to meet these challenges. This demo paper presents the prototype of ComDeX, which is designed to facilitate efficient data exchange in smart communities using a federation of message brokers. The prototype harnesses NGSI-LD and MQTT standards along with an advertisement-based mechanism to enable dynamic data exchange. We detail its implementation and key functionalities, demonstrating its applicability through scenarios that mimic real-world smart communities.