The Internet of Things connects billions of objects leveraging the potential of transforming various aspects of society and for improving the quality of lives. The Swarm is an IoT approach in which devices are capable of cooperating with one another in an autonomous and spontaneous manner to fulfill a given mission. Traditional homogeneous middleware cannot handle thevast heterogeneity of devices in the Internet of Things. Previously, we created a heterogeneousand distributed software agent, called Swarm Broker, which offers common services to help devices to interact with each other. In this paper we introduce the concept of a Minimum Broker,the core software that shall be running in resourceconstrained devices to be part of the SwarmWealso present an implementation of the Minimum Broker and its integration in the Swarm. Additionally, a use case was deployed and the Minimum Broker evaluated.