The enterprise service bus (ESB) is a concept and resulting set of software products that came to fruition in the early 2000s. The ESB was designed to contain the complexity of connecting heterogeneous applications, including the entire organization’s business logic and data. These concepts have fallen out of favor with the advent of microservices and Kafka. This existing definition of ESB’s is no longer useful to us; in this talk, we’ll introduce a modern definition of the ESB, with Kafka at its heart.