An SCA composite is used to assemble components in logical groupings. It is the basic unit of composition within an SCA System. An SCA Composite contains a set of Components, Services, References and the Wires that interconnect them. Composites are component implementations in higher-level composites in other words composites can have components that are implemented by composites.

A composite has the following normative characteristics:

• It defines a boundary for Component visibility. Components may not be directly referenced outside of the composite that contains them.
• It can be used as a unit of deployment. Composites are used to contribute business services to an SCA system.