subservice

A subservice is a term used in service-oriented architecture and IT service management to refer to a service that forms part of a larger service. A subservice delivers a distinct function or feature that contributes to the overall value of the parent service. Subservices may be provided by the same organization and integrated into a single offering, or they may be supplied by external vendors as modular components.

In ITSM and service catalogs, subservices are used to model the decomposition of complex services. Each subservice can have its own ownership, performance metrics, dependencies, and, in many cases, service level agreements. This allows operators to provision, monitor, and charge for individual components within a bundle, enabling granular governance and more flexible service design.

In cloud and software engineering, the term often overlaps with microservices or modular components. A subservice can be independently scalable, versioned, and deployed, but typically remains bound by the overall lifecycle and policy of the parent service. Failure or latency in one subservice can affect the parent service and other subservices, necessitating fault isolation and resilience measures.

Management practices include mapping subservices in a service catalog or product portfolio, defining interfaces, and aligning with organizational service definitions. Not all organizations use a formal 'subservice' term; equivalents include component service, child service, or module within a composite offering. Related concepts include service-oriented architecture, ITIL, and microservices.