Sean Seefried and I have just released an implementation of the client and worker protocols for Majordomo, as specified at http://rfc.zeromq.org/spec:7 While it's not yet complete (the client won't try reconnecting, for instance, and has a hardcoded timeout), we're already finding it useful for ninjablocks.com The mdp_client executable is also useful for poking majordomo servers from the command line. http://hackage.haskell.org/package/majordomo https://github.com/ninjablocks/majordomo Cheers, Mark Wotton