The Java Message Service (JMS) is a Java API that allows applications to communicate with each other using a common set of interfaces. The JMS API provides messaging interfaces, but not the implementations.

A JMS provider, such as Software AG Universal Messaging or webMethods Broker, is a messaging system that supports the JMS message interfaces and provides administrative and control features. It supports the routing and delivery of JMS messages.

JMS clients are the programs or components, written in Java, that produce and consume messages.