Thanks for your answer timfox, Yes I have. I wrote a small piece of code that store a certain number of messages in a buffer before sending all of them in a single JMS message (that's what I called concatenate). This increase considerably the performances (it takes quite the same time to send one message than 1000 messages over a JMS message). But I would like to know if there is a way that Jboss ESB do it for me? My problem is that I have to manage a buffer and if I store 1000 messages before sending the JMS message I can pray for my app not to crash otherwise I could lose 1000 messages! Thanks in advance, Simon (And sorry if my English is not perfect :-S) View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4225541#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...