RabbitMQ - RabbitMQ is an open source message broker software.
Apache Camel - Apache Camel is a versatile open-source integration framework based on known enterprise integration patterns.
Apache ActiveMQ - Apache ActiveMQ is an open source messaging and integration patterns server.
Apache Kafka - Apache Kafka is an open-source message broker project developed by the Apache Software Foundation written in Scala.
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ZeroMQ - ZeroMQ is a high-performance asynchronous messaging library.