diff -r 000000000000 -r 6474c204b198 addon-sdk/source/lib/sdk/addon/events.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/addon-sdk/source/lib/sdk/addon/events.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,54 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+'use strict';
+
+module.metadata = {
+  'stability': 'experimental'
+};
+
+let { request: hostReq, response: hostRes } = require('./host');
+let { defer: async } = require('../lang/functional');
+let { defer } = require('../core/promise');
+let { emit: emitSync, on, off } = require('../event/core');
+let { uuid } = require('../util/uuid');
+let emit = async(emitSync);
+
+// Map of IDs to deferreds
+let requests = new Map();
+
+// May not be necessary to wrap this in `async`
+// once promises are async via bug 881047
+let receive = async(function ({data, id, error}) {
+  let request = requests.get(id);
+  if (request) {
+    if (error) request.reject(error);
+    else request.resolve(clone(data));
+    requests.delete(id);
+  }
+});
+on(hostRes, 'data', receive);
+
+/*
+ * Send is a helper to be used in client APIs to send
+ * a request to host
+ */
+function send (eventName, data) {
+  let id = uuid();
+  let deferred = defer();
+  requests.set(id, deferred);
+  emit(hostReq, 'data', {
+    id: id,
+    data: clone(data),
+    event: eventName
+  });
+  return deferred.promise;
+}
+exports.send = send;
+
+/*
+ * Implement internal structured cloning algorithm in the future?
+ * http://www.whatwg.org/specs/web-apps/current-work/multipage/common-dom-interfaces.html#internal-structured-cloning-algorithm
+ */
+function clone (obj) JSON.parse(JSON.stringify(obj || {}))