Kafka Streams

What Kafka Streams is

Kafka Streams is a client library for building applications and microservices that read and write data in Kafka clusters. It processes Kafka data with event-time handling, windowing, and real-time queries of application state. The Streams DSL provides operations such as mapping, filtering, joining, and aggregation, while the Processor API allows custom processors and state stores. Fault-tolerant local state supports stateful work such as windowed joins and aggregations, and the library supports exactly-once processing semantics. Applications can start on one machine and scale across multiple machines, and can run in containers, virtual machines, on bare metal, or in cloud environments. Kafka Streams uses Kafka as its messaging layer, so it does not require a separate processing cluster. It supports Java and Scala and integrates with Kafka security features for transit encryption, authentication, and authorization. The software is free under Apache License 2.0. The Apache Software Foundation says it does not provide formal or commercial support for its packages; project communication is available through community mailing lists.