Implementations exist as proprietary software, provided as a service, open source software, or a hardware-based solution.
There are a number of open source choices of messaging middleware systems, including Apache ActiveMQ, Apache Kafka, Apache Qpid,[REF] Beanstalkd, HTTPSQS[REF]JBoss Messaging, JORAM, RabbitMQ, Sun Open Message Queue, and Tarantool.