The disclosed architecture is an application program interface (API) that includes a collection of class members defined in a single class for accessing mailboxes in messaging storage locations in an enterprise organization. Each mailbox in the organization has an identity that primarily encapsulates at least a mailbox server name, a unique mailbox database GUID (globally unique identifier), and a unique mailbox GUID. By encapsulating information associated with a mailbox into one class, database lookups can be optimized and a single source of mailbox information provided for both authentication and display purposes. Other information can also be encapsulated.