What is the difference between ActiveMQ and Kafka?

ActiveMQ is a traditional JMS-compliant message broker built for flexible routing (queues, topics, virtual destinations) and enterprise integration patterns. Kafka is a distributed, log-based streaming platform built for very high-throughput, ordered, replayable event streams.

ActiveMQ typically removes a message once it's acknowledged; Kafka retains messages on disk for a configured retention period regardless of consumption, so multiple independent consumer groups can replay the same log at their own pace. ActiveMQ scales mainly through networks of brokers or vertical scaling, while Kafka is designed from the ground up to scale horizontally via partitioned topics across a cluster. On ordering, ActiveMQ can guarantee order within a Queue, whereas Kafka guarantees order only within a partition.

Choose ActiveMQ when you need per-message transactional semantics, complex routing, or protocol variety (JMS/AMQP/MQTT/STOMP). Choose Kafka when you need to process massive event volumes, replay history, or feed multiple downstream systems from the same stream.