diff --git a/README.md b/README.md
index 00bdb30..159c0b8 100644
--- a/README.md
+++ b/README.md
@@ -23,8 +23,10 @@ As a submodule of your project
     var message = {
         registration_id: 'Device registration id', // required
         collapse_key: 'Collapse key', 
-        'data.key1': 'value1',
-        'data.key2': 'value2'
+        data: {
+            key1: 'value1',
+            key2: 'value2'
+        }
     };
     
     gcm.send(message, function(err, messageId){
diff --git a/lib/gcm.js b/lib/gcm.js
index b8cccea..07c1570 100644
--- a/lib/gcm.js
+++ b/lib/gcm.js
@@ -1,6 +1,5 @@
 var util = require('util');
 var https = require('https');
-var querystring = require('querystring');
 var emitter = require('events').EventEmitter;
 var retry = require('retry');
 
@@ -30,11 +29,11 @@ GCM.prototype.send = function(packet, cb) {
     var operation = retry.operation();
 
     operation.attempt(function(currentAttempt) {
-        var postData = querystring.stringify(packet);
+        var postData = JSON.stringify(packet);
         var headers = {
             'Host': self.gcmOptions.host,
             'Authorization': 'key=' + self.apiKey,
-            'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8',
+            'Content-Type': 'application/json',
             'Content-length': postData.length
         };
         self.gcmOptions.headers = headers;
@@ -44,7 +43,7 @@ GCM.prototype.send = function(packet, cb) {
         var request = https.request(self.gcmOptions, function(res) {
             var data = '';
 
-            if (res.statusCode == 503) {
+            if (res.statusCode >= 501 && res.statusCode < 600) {
                 // If the server is temporary unavailable, the C2DM spec requires that we implement exponential backoff
                 // and respect any Retry-After header
                 if (res.headers['retry-after']) {
@@ -65,26 +64,21 @@ GCM.prototype.send = function(packet, cb) {
             }
 
             function respond() {
-                var error = null, id = null;
 
-                if (data.indexOf('Error=') === 0) {
-                    error = data.substring(6).trim();
-                }
-                else if (data.indexOf('id=') === 0) {
-                    id = data.substring(3).trim();
-                }
-                else {
-                    // No id nor error?
-                    error = 'InvalidServerResponse';
-                }
+                if(res.statusCode >= 200 && res.statusCode < 300) {
+                    //Success
+                    self.emit('sent', null, JSON.parse(data))
+                } else {
+                    //Error
 
-                // Only retry if error is QuotaExceeded or DeviceQuotaExceeded
-                if (operation.retry(['QuotaExceeded', 'DeviceQuotaExceeded', 'InvalidServerResponse'].indexOf(error) >= 0 ? error : null)) {
-                    return;
-                }
+                    if (data == "DeviceMessageRateExceeded" || data == "DEVICE_MESSAGE_RATE_EXCEEDED") {
+                        if (operation.retry(data)) {
+                            return;
+                        }
+                    }
 
-                // Success, return message id (without id=)
-                self.emit('sent', error, id);
+                    self.emit('sent', data, null)
+                }
             }
 
             res.on('data', function(chunk) {