In one embodiment, a graphical user interface (“GUI”) enables the efficient composition and execution of a test of a message-based application, Web application, or SOA systems' capacity to receive, process and respond to message traffic. The GUI may be used to generate a test composition by dragging and dropping message clips onto one or more tracks. Each clip includes one or more message, with each track being organized into one or more bands. Each track and each band may run contemporaneously to send messages to a target device or application. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure.