Amazon Simple Queue Service is a fully managed message queuing service.

RabbitMQ is an open source message broker software.

Celery helps innovative companies set up pre-order or custom crowdfunding campaigns anywhere.

ZeroMQ is a high-performance asynchronous messaging library.

A realtime distributed messaging platform.

Gearman provides a generic application framework to farm out work to other machines or processes that are better suited to do the work.

CloudAMQP automates every part of setup, running and scaling of RabbitMQ clusters. Available on all major cloud and application platforms.

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

Kestrel is a simple, distributed message queue written on the JVM.

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

Sparrow is a minimal e-mail application designed to keep things simple and efficient.