A software component that encapsulates run-time rule processing elements. The component instances provide a "ready to run" business rule application. A decision service offers a business interface with methods. The implementation of the interface is calling a business rule engine.

A decision service component is mostly stateless and simplifies the process of integrating business rules with popular application platforms such as JSE, JEE, and a Web service. In the context of a BRMS application it is also named rule service.