diff --git a/lib/relay.js b/lib/relay.js
index 78c159b..9b66d26 100644
--- a/lib/relay.js
+++ b/lib/relay.js
@@ -1,10 +1,15 @@
 'use strict';
 
 var url = require('url');
-var PromiseA = require('bluebird');
 var sni = require('sni');
 var Packer = require('proxy-packer');
 var PortServers = {};
+var PromiseA;
+try {
+  PromiseA = require('bluebird');
+} catch(e) {
+  PromiseA = global.Promise;
+}
 
 function timeoutPromise(duration) {
   return new PromiseA(function (resolve) {