Apache Kafka is an open-source distributed event streaming platform that is designed for applications that need to be distributed across a cluster, following a microservices pattern, and built on an architecture that allows for event-driven, pub-sub communication. It is particularly well-suited for use cases such as real-time data streaming, data integration, and event-driven architectures. It is built on a distributed, partitioned, and replicated log data structure, which allows it to handle high volumes of data and support horizontal scaling.