XActor is a distributed transaction manager that affords transactional remote invocations over an open-ended set of transports. Its support to transactional interactions is dynamic, in the sense that the transaction manager fully exploits a collection of RMI mechanisms and transport protocols that grows with the addition of plug-in modules to running instances of XActor. A distributed transaction can employ any combination of the transports that the currently installed plug-ins provide. Two-phase commit (logging and failure recovery included) runs over any such combination of transports. Aimed at server-side application containers, XActor can be integrated with those systems in a way that allows its plug-in modules to take advantage of the dynamic deployment facilities of the container environment.