The Instaclustr team explains how stream processing works in Kafka Streams:
Kafka Streams is a client library providing organizations with a particularly efficient framework for processing streaming data. It offers a streamlined method for creating applications and microservices that must process data in real-time to be effective. Using the Streams API within Apache Kafka, the solution fundamentally transforms input Kafka topics into output Kafka topics. The benefits are important: Kafka Streams pairs the ease of utilizing standard Java and Scala application code on the client end with the strength of Kafka’s robust server-side cluster architecture.
Read on for an overview of how it works. And if you haven’t already, check out the prior post on Kafka so that you can experience the same slight mental perturbations I did when reading about “real-time” responses.