RabbitMQ is an open-source message-broker software that implements the Advanced Message Queuing Protocol (AMQP). It is designed to handle large numbers of messages and route them to the appropriate recipient. RabbitMQ is written in the Erlang programming language and is built on the Open Telecom Platform framework. It allows for reliable, asynchronous messaging between applications or systems, and it supports a variety of messaging patterns such as point-to-point, publish-subscribe, and request-response. RabbitMQ is often used in distributed systems, microservices architectures, and in systems that need to handle high levels of incoming messages and maintain data consistency.