This specification describes coordination types that are used with the extensible coordination framework described in the WS-Coordination specification. It defines two coordination types: Atomic Transaction (AT) and Business Activity (BA). Developers can use either or both of these coordination types when building applications that require consistent agreement on the outcome of distributed activities. Composable Architecture By using the SOAP [SOAP] and WSDL [WSDL] extensibility model, SOAP-based and WSDL-based specifications are designed to work together to define a rich Web services environment. As such, WS-Transaction by itself does not define all features required for a complete solution. WS-Transaction is a building block used with other specifications of Web services (e.g., WS-Coordination, WS-Security) and application-specific protocols that are able to accomodate a wide variety of coordination protocols related to the coordination actions of distributed applications. Status of this Document WS-Transaction and related specifications are provided for use as-is and for review and evaluation only. Microsoft, BEA, and IBM will solicit your contributions and suggestions in the near future. Microsoft, BEA, and IBM make no warranties or representations regarding the specification in any manner whatsoever. Acknowledgements The following individuals have provided invaluable input into the design of the WS-Transaction specification: Francisco Curbera, IBM Gert Drapers, Microsoft