meteor-debug-ddp.js

//http://stackoverflow.com/questions/25373648/how-to-view-meteor-ddp-traffic
if (Meteor.isClient) {

  // log sent messages
  var _send = Meteor.connection._send;
  Meteor.connection._send = function (obj) {
    console.log("send", obj);
    _send.call(this, obj);
  };

  // log received messages
  Meteor.connection._stream.on('message', function (message) {
    console.log("receive", JSON.parse(message));
  });
}