Kafka Streams is a client library for building applications and microservices, where the input and output data are stored in an Apache Kafka cluster. It is a data processing and transformation library within Kafka used as a messaging service. Kafka Streams combines the simplicity of writing and deploying standard Java and Scala applications on the client side with the benefits of Kafkas server-side technology.

Some key features of Kafka Streams include:

• Data parallelism: Kafka Streams greatly simplifies the stream processing from topics and provides data parallelism.
• Processing and analyzing data: Kafka Streams is a client library for processing and analyzing data stored in Kafka and either write the resulting data back to Kafka or send the final.
• Easy to use: Kafka Streams is an easy data processing and transformation library within Kafka used as a messaging service.

To get started with Kafka Streams, you can sign up for Confluent, the fully managed cloud-native service for Apache Kafka, or download Apache Kafka, the self-managed, enterprise-grade distribution of Apache Kafka. There are also resources available such as a free video course, quick start guide, and recommended reading.