A single programming model is provided for accessing a plurality of distinct message transports while developing one or more applications for message delivery between two endpoints. The programming model allows for independently configurable assurances and features for transporting the messages. The configurable assurances may be selected from at least once delivery, at most once message delivery, in order message delivery, and message time to live. The independently chosen features may include a session state storage, an extension of time to live, and transacted message buffering.