1. Eclipse Paho project provides open-source client implementations of MQTT and MQTT-SN messaging protocols.

  2. IBM MQ is messaging middleware that simplifies and accelerates the integration of diverse applications and data across multiple platforms.

  3. Move data everywhere it's needed, instantly and automatically

  4. CloudMQTT implements MQ Telemetry Transport protocol for carrying out messaging using a publish/subscribe message queueing model.

  5. A lightweight message queue for Node.js that requires a Redis server.

  6. Finagle is a protocol-agnostic RPC system.

  7. Scalable MQTT message broker.

  8. NATS Server is an open source messaging system for cloud native applications, IoT messaging, and microservices architectures.

  9. Simple pub/sub messaging for the web

  10. IronMQ is the distributed systems together by providing a reliable way to communicate between services and components.

  11. Apache Qpid makes messaging tools that speak AMQP and support many languages and platforms.

  12. Job queue for Android to easily schedule jobs that run in the background, improving UX and application stability.