Apache ActiveMQ is a popular open source messaging service written in Java. It was originally created in 2004 by LogicBlaze as an open source message broker and later donated to the Apache Software Foundation in 2007.

Like all other message brokers, it serves as a communication platform between multiple applications existing on separate servers or written in different languages. It implements JMS (Java Message Service) and supports several messaging protocols including AMQP and MQTT.

Features

Multiple connection protocols are supported.

Schedule delayed deliveries, which aren’t available with Kafka.

Database row-level locking techniques, file system and other modes are used for high-availability.

Along with simple authentication and JAAS authentication, ActiveMQ also offers an API for custom authentication plug-ins.

Along with vertical scaling, built-in functionality for horizontal scaling (called Network of Brokers) is also supported.

Offers support for several transport protocols, including STOMP, REST, and OpenWire.