A personal messaging application programming interface can be utilized by a developer in order to add groupware functionality to an application. The interface can include various schemas and providers that allow the schemas to connect to a collaboration server which provides the groupware functionality. The schemas can further include item and container classes and can extend other schemas so as to provide functionality that is more specific to the collaboration server. The items and containers can represent various entities on the collaboration server. The providers can use stubs in order to create connections to the collaboration server and can implement the schema hierarchy so as to map the functionality defined by the schema into various core calls on the collaboration server.