An Application Service is a unit of functionality exposed by an application that supports business operations or other applications. It is not the application itself it is the behavior the application provides. An Application Service is: • Abstracted from the internal workings of the application Consumers of the service do not need to know how the application is built. • Consumable by business processes, business services, or other applications Example: A business process “Calculate Claim” uses the “Claim Rules Service”. • Stable even if the underlying technology changes The application may be rewritten or replatformed, but its services remain conceptually the same. • Defined by what it provides, not how it is implemented Example: “Eligibility Verification Service” can be delivered by: • a mainframe system, • a microservice, • a vendor SaaS platform, but the service definition does not change.