Bindings are used by external services and entry points. External services use bindings to describe the access mechanism used to call an external service (which can be a service provided by another SCA module). Entry points use bindings to describe the access mechanism that clients (which can be a client from another SCA module) have to use to call the service published by the entry point.

SCA supports the use of multiple different types of bindings. Examples include SCA service, Web service, stateless session EJB, data base stored procedure, EIS service. An SCA runtime must provide support for SCA service and Web service binding types. SCA provides an extensibility mechanism by which an SCA runtime can add support for additional binding types. For details on how additional binding types are defined, see the section on the Extension Model.