Hi all. I need to implement an interaction with an external web service. The external webservice basically can either provide or accept messages from my zope application. The messages are either produced by my application (and need to be "sent" to the external application via web service) or produced by the external application, and must be processed by mine. I'm asking then for best practice for this sort of interaction. Following what I have read in other threads, I would assume that, for example for sending, I should do something like: - create a queue of objects which needs to be sent, in one transaction; - sent the objects which need to be sent, in another transaction; The problem, of course, is to minimize (if not avoid at all) the chance to have a Conflict with a double sending of the message. In some sense, this is very close to sending an email via an smtp server, therefore, I assume I should at the right products to look for inspirations. Thanks you all for your time. Marco -- Marco Bizzarri http://iliveinpisa.blogspot.com/