ActiveMQ is a popular, open-source, multi-protocol implementation of message-oriented middleware (MOM) with enterprise features written in Java, used to send messages between two applications, or two components inside an application. It supports a wide range of Cross-Language Clients from Java, C, C++, C#, Ruby, Perl, Python, PHP, and transport protocols such as OpenWire, STOMP, MQTT, AMQP, REST, and WebSockets. Some of its use cases include transactional messaging, clustering and general-purpose async messaging model, web streaming of data, RESTful API to messaging using HTTP, and much more.