diff --git a/sylk/applications/webrtcgateway/models/firebase.py b/sylk/applications/webrtcgateway/models/firebase.py
new file mode 100644
index 0000000..0826ea5
--- /dev/null
+++ b/sylk/applications/webrtcgateway/models/firebase.py
@@ -0,0 +1,80 @@
+
+from sipsimple.util import ISOTimestamp
+
+from .jsonobjects import BooleanProperty, IntegerProperty, StringProperty, ObjectProperty, FixedValueProperty, LimitedChoiceProperty, AbstractObjectProperty
+from .jsonobjects import JSONObject
+
+
+class NotificationData(JSONObject):
+    body = StringProperty(optional=True)
+    sound = StringProperty(optional=True)
+    title = StringProperty(optional=True)
+    subtitle = StringProperty(optional=True)
+
+
+class ApplicationData(JSONObject):
+    sylkrtc = AbstractObjectProperty()
+
+
+class FirebaseRequest(JSONObject):
+    priority = LimitedChoiceProperty(['normal', 'high'], optional=True, default='high')
+    content_available = BooleanProperty(optional=True, default=True)
+    time_to_live = IntegerProperty(optional=True)  # for how long should the system try to deliver the notification (default is 4 weeks)
+    to = StringProperty()
+    notification = ObjectProperty(NotificationData)
+    data = ObjectProperty(ApplicationData)
+
+    def __init__(self, token, event, **kw):
+        super(FirebaseRequest, self).__init__(to=token, data=dict(sylkrtc=event), notification=event.notification, **kw)
+
+
+# Event base classes (abstract, should not be used directly)
+
+class SylkRTCEventBase(JSONObject):
+    timestamp = StringProperty()
+
+    def __init__(self, **kw):
+        kw['timestamp'] = str(ISOTimestamp.utcnow())
+        super(SylkRTCEventBase, self).__init__(**kw)
+        self.notification = NotificationData(body=self.notification_body)
+        if self.notification_sound is not None:
+            self.notification.sound = self.notification_sound
+
+    @property
+    def notification_body(self):
+        raise NotImplementedError
+
+    notification_sound = None
+
+
+class CallEventBase(SylkRTCEventBase):
+    event = None  # specified by subclass
+    originator = StringProperty()
+    destination = StringProperty()
+
+    @property
+    def notification_body(self):
+        return '{0.event_description} from {0.originator}'.format(self)
+
+    @property
+    def event_description(self):
+        return self.event.replace('-', ' ').capitalize()
+
+
+# Events to use used in a FirebaseRequest
+
+class IncomingCallEvent(CallEventBase):
+    event = FixedValueProperty('incoming-call')
+
+
+class MissedCallEvent(CallEventBase):
+    event = FixedValueProperty('missed-call')
+
+
+class ConferenceInviteEvent(CallEventBase):
+    event = FixedValueProperty('conference-invite')
+    room = StringProperty()
+
+    @property
+    def notification_body(self):
+        return '{0.event_description} from {0.originator} to room {0.room}'.format(self)
diff --git a/sylk/applications/webrtcgateway/push.py b/sylk/applications/webrtcgateway/push.py
index 937ff76..c6a83e5 100644
--- a/sylk/applications/webrtcgateway/push.py
+++ b/sylk/applications/webrtcgateway/push.py
@@ -1,81 +1,65 @@
 
 import json
 
-from sipsimple.util import ISOTimestamp
 from twisted.internet import defer, reactor
 from twisted.web.client import Agent
 from twisted.web.iweb import IBodyProducer
 from twisted.web.http_headers import Headers
 from zope.interface import implementer
 
-from sylk.applications.webrtcgateway.configuration import GeneralConfig
-from sylk.applications.webrtcgateway.logger import log
+from .configuration import GeneralConfig
+from .logger import log
+from .models import firebase
 
 
 __all__ = 'incoming_session', 'missed_session'
 
 
 agent = Agent(reactor)
 headers = Headers({'User-Agent': ['SylkServer'],
                    'Content-Type': ['application/json'],
                    'Authorization': ['key=%s' % GeneralConfig.firebase_server_key]})
 FIREBASE_API_URL = 'https://fcm.googleapis.com/fcm/send'
 
 
 @implementer(IBodyProducer)
 class StringProducer(object):
     def __init__(self, data):
         self.body = data
         self.length = len(data)
 
     def startProducing(self, consumer):
         consumer.write(self.body)
         return defer.succeed(None)
 
     def pauseProducing(self):
         pass
 
     def stopProducing(self):
         pass
 
 
 def incoming_session(originator, destination, tokens):
     for token in tokens:
-        data = dict(to=token, notification={}, data={'sylkrtc': {}}, content_available=True)
-        data['notification']['body'] = 'Incoming call from %s' % originator
-        data['notification']['sound'] = 'Blow'
-        data['priority'] = 'high'
-        data['time_to_live'] = 60    # don't deliver if phone is out for over a minute
-        data['data']['sylkrtc']['event'] = 'incoming_session'
-        data['data']['sylkrtc']['originator'] = originator
-        data['data']['sylkrtc']['destination'] = destination
-        data['data']['sylkrtc']['timestamp'] = str(ISOTimestamp.utcnow())
-        _send_push_notification(json.dumps(data))
+        request = firebase.FirebaseRequest(token, event=firebase.IncomingCallEvent(originator=originator, destination=destination), time_to_live=60)
+        _send_push_notification(json.dumps(request.__data__))
 
 
 def missed_session(originator, destination, tokens):
     for token in tokens:
-        data = dict(to=token, notification={}, data={'sylkrtc': {}}, content_available=True)
-        data['notification']['body'] = 'Missed call from %s' % originator
-        data['notification']['sound'] = 'Blow'
-        data['priority'] = 'high'
-        # No TTL, default is 4 weeks
-        data['data']['sylkrtc']['event'] = 'missed_session'
-        data['data']['sylkrtc']['originator'] = originator
-        data['data']['sylkrtc']['destination'] = destination
-        data['data']['sylkrtc']['timestamp'] = str(ISOTimestamp.utcnow())
-        _send_push_notification(json.dumps(data))
+        request = firebase.FirebaseRequest(token, event=firebase.MissedCallEvent(originator=originator, destination=destination))
+        _send_push_notification(json.dumps(request.__data__))
 
 
 @defer.inlineCallbacks
 def _send_push_notification(payload):
     if GeneralConfig.firebase_server_key:
         try:
             r = yield agent.request('POST', FIREBASE_API_URL, headers, StringProducer(payload))
         except Exception as e:
             log.info('Error sending Firebase message: %s', e)
         else:
             if r.code != 200:
                 log.warn('Error sending Firebase message: %s' % r.phrase)
     else:
         log.warn('Cannot send push notification: no Firebase server key configured')