Build an integration service when you want a flow to interact with an external system.
For example, you may want users to choose from a list of products available from a common site on the internet. In that case, you can build an integration service that calls a web service to display the list of options. Integration services are the only services that can include Web Service Integration and Java Integration components as well as content integration. For more information about inbound and outbound integrations, see Integrating with web services, Java and databases.