Apache Kafka is an open-source stream-processing software platform developed by LinkedIn and donated to the Apache Software Foundation, written in Scala and Java. Kafka is designed for high-throughput, fault-tolerant, and real-time data processing. It provides a distributed messaging system for publishing, subscribing to, and storing streams of records in a fault-tolerant and durable manner. Kafka's architecture consists of producers that publish data to topics, consumers that subscribe to topics and process data in real-time, and brokers that manage the storage and replication of data across a cluster of servers. Kafka is used for use cases such as real-time analytics, log aggregation, event sourcing, and messaging systems. It is highly scalable and can handle millions of messages per second with low latency. Kafka is used by thousands of companies worldwide, including Netflix, Uber, Airbnb, and LinkedIn, to build scalable and reliable data pipelines and streaming applications.