What is Apache Kafka and what problem does it solve?

Apache Kafka is a distributed event streaming platform that acts as a durable, ordered, fault-tolerant message log. It solves the problem of high-throughput, real-time data integration between heterogeneous systems. Unlike traditional message queues that delete messages after delivery, Kafka retains messages for a configurable period, enabling replay, auditing, and decoupling producers from consumers. It handles millions of events per second while maintaining low latency.

Expected key concepts: distributed, event streaming, durable, ordered, fault-tolerant, message log, high-throughput, decoupling, replay, retention