A persistent object maintained by SecureTransport that links an account with an application instance. Subscription objects are used to represent user account subscriptions to the applications. A SecureTransport administrator can subscribe multiple user accounts to the application instance. Subscription objects are also used to represent the application instance connection to a service account. The custom application developer defines how many service accounts the custom application needs and what purpose each service account serves. A SecureTransport administrator subscribes the service accounts when creating the application instance.