An **Application Service** is an entity within the [[Service Delivery (CSDM domain)|Service Delivery domain]] of the [[Common Service Data Model|Common Service Data Model]] (CSDM), a reference architecture developed by [[ServiceNow|ServiceNow]] that provides prescriptive guidance on service-related definitions and data modeling within the ServiceNow AI Platform. An Application Service is a [[Service Instance (CSDM)|Service Instance]] type representing a logical or designated instance of a [[Business Application (CSDM)|Business Application]] or application function based on a deployed and operational system plus application/software stack, such as an organization's email system or customer-facing website. Application Services are operational [[Configuration item|configuration items]] used for impact analysis in [[Incident management (ITSM)|Incident]], [[Problem management|Problem]], and [[Change management (ITSM)|Change]] processes. Instances may be designated by environment (Development, Test, Production) or by region, line of business, or geography (EMEA, NA, APAC). Application Services can be created through multiple population methods: Top-Down Discovery via [[Service Mapping (ServiceNow)|Service Mapping]] (cmdb_ci_service_discovered), Manual mapping (cmdb_ci_service_discovered), Tags (cmdb_ci_service_by_tags), Calculated (cmdb_ci_service_calculated), or [[Dynamic CI Group (CSDM)|Dynamic CI Group]] using Query Builder queries (cmdb_ci_query_based_service with Service Classification of "Application Service"). The "New Application Service" wizard allows administrators to provide basic details, choose a data population method, and preview the service prior to committing. Application Services underpin [[Business Service (CSDM)|business services]] or [[Technology Management Service (CSDM)|technology management services]] and should be related to their parent [[Business Application (CSDM)|Business Application]] using the "Uses::Used by" [[CMDB relationship|CMDB relationship]].