RabbitMQ is an open source message broker software (message-oriented middleware), using the standard Advanced Message Queuing Protocol (AMQP). The RabbitMQ server is written in Erlang,t he source code is released under the Mozilla Public License.
The RabbitMQ project consists of several parts:
The RabbitMQ exchange server itself
Gateways for HTTP, XMPP and STOMP protocols
AMQP client libraries for Java and .NET Framework. (AMQP clients for other languages are available from other vendors)
The "Shovel" plug-in that takes care of copying (replicating) messages from one broker to another