Apache Kafka is a distributed, scalable messaging technology designed as a backbone for service-based systems to exchange and buffer events. It scales well, runs always-on, and retains datasets long-term. Kafka provides durability through replication, allowing messages to be written to multiple machines so that data is not lost in case of machine failure. The system also features a log-structured approach, making reads and writes sequential operations, which helps with overall performance and makes it suitable for storing messages longer term. Kafka's throughput control feature allows services to operate within strictly enforced SLAs by allocating defined bandwidth to specific services. Strong ordering guarantees can be achieved through partitioning messages that require relative or global ordering. The system also includes a compacted topic feature, which reduces the growth of datasets and makes them easier to move from machine to machine. Kafka supports event sourcing and stream processing, making it an ideal choice for building event-driven systems. It is designed to be scalable, with production clusters starting at three machines and growing to hundreds. The system also includes features such as transactions, schema validation, and batching, which provide a high degree of control over data movement and storage.