By default, Lagom Framework supports an embedded Kafka server as a message broker in a development environment to exchange information or data between services.
This embedded Kafka server's default port number is 9092. Kafka uses ZooKeeper, which is a distributed coordination service. ZooKeeper server's default port number is 2181.
When we start our Lagom Reactive System or service using the sbt runAll command, it starts both the embedded server's Kafka and Zookeeper. We can find the Lagom's implementation of Kafka and Zookeeper in the lagom-kafka-server_2.11-1.3.10.jar file.
If required, we can configure Kafka externally by updating the build.sbt file. We will explore more about this in our examples: