diff --git a/sylk/applications/webrtcgateway/models/sylkrtc.py b/sylk/applications/webrtcgateway/models/sylkrtc.py
index c3230e5..814e2b5 100644
--- a/sylk/applications/webrtcgateway/models/sylkrtc.py
+++ b/sylk/applications/webrtcgateway/models/sylkrtc.py
@@ -1,202 +1,201 @@
 
-import re
-
 from jsonmodels import models, fields, errors, validators
 from sipsimple.core import SIPURI, SIPCoreError
 
 __all__ = ('AccountAddRequest', 'AccountRemoveRequest', 'AccountRegisterRequest', 'AccountUnregisterRequest',
            'SessionCreateRequest', 'SessionAnswerRequest', 'SessionTrickleRequest', 'SessionTerminateRequest',
            'AckResponse', 'ErrorResponse',
            'ReadyEvent')
 
-SIP_PREFIX_RE = re.compile('^sips?:')
-
 
 class DefaultValueField(fields.BaseField):
     def __init__(self, value):
         self.default_value = value
         super(DefaultValueField, self).__init__()
 
     def validate(self, value):
         if value != self.default_value:
             raise errors.ValidationError('%s does not match the expected value %s' % (value, self.default_value))
 
     # noinspection PyMethodOverriding
     def get_default_value(self):
         return self.default_value
 
 
 class URIValidator(object):
     @staticmethod
     def validate(value):
-        uri = SIP_PREFIX_RE.sub('', value)
+        if value.startswith(('sip:', 'sips:')):
+            uri = value
+        else:
+            uri = 'sip:' + value
         try:
-            SIPURI.parse('sip:%s' % uri)
+            SIPURI.parse(uri)
         except SIPCoreError:
             raise errors.ValidationError('invalid URI: %s' % value)
 
 
 class URIListValidator(object):
     @staticmethod
     def validate(values):
         for item in values:
             URIValidator.validate(item)
 
 
 class OptionsValidator(object):
     def __init__(self, options):
         self.options = options
 
     def validate(self, value):
         if value not in self.options:
             raise errors.ValidationError('invalid option: %s' % value)
 
 
 # Base models
 
 class SylkRTCRequestBase(models.Base):
     transaction = fields.StringField(required=True)
 
 
 class SylkRTCResponseBase(models.Base):
     transaction = fields.StringField(required=True)
 
 
 # Miscellaneous models
 
 class AckResponse(SylkRTCResponseBase):
     sylkrtc = DefaultValueField('ack')
 
 
 class ErrorResponse(SylkRTCResponseBase):
     sylkrtc = DefaultValueField('error')
     error = fields.StringField(required=True)
 
 
 class ICECandidate(models.Base):
     candidate = fields.StringField(required=True)
     sdpMLineIndex = fields.IntField(required=True)
     sdpMid = fields.StringField(required=True)
 
 
 class ReadyEvent(models.Base):
     sylkrtc = DefaultValueField('event')
     event = DefaultValueField('ready')
 
 
 # Account models
 
 class AccountRequestBase(SylkRTCRequestBase):
     account = fields.StringField(required=True, validators=[URIValidator])
 
 
 class AccountAddRequest(AccountRequestBase):
     sylkrtc = DefaultValueField('account-add')
     password = fields.StringField(required=True, validators=[validators.Length(minimum_value=1, maximum_value=9999)])
     display_name = fields.StringField(required=False)
     user_agent = fields.StringField(required=False)
 
 
 class AccountRemoveRequest(AccountRequestBase):
     sylkrtc = DefaultValueField('account-remove')
 
 
 class AccountRegisterRequest(AccountRequestBase):
     sylkrtc = DefaultValueField('account-register')
 
 
 class AccountUnregisterRequest(AccountRequestBase):
     sylkrtc = DefaultValueField('account-unregister')
 
 
 class AccountDeviceTokenRequest(AccountRequestBase):
     sylkrtc = DefaultValueField('account-devicetoken')
     old_token = fields.StringField(required=False)
     new_token = fields.StringField(required=False)
 
 
 # Session models
 
 class SessionRequestBase(SylkRTCRequestBase):
     session = fields.StringField(required=True)
 
 
 class SessionCreateRequest(SessionRequestBase):
     sylkrtc = DefaultValueField('session-create')
     account = fields.StringField(required=True, validators=[URIValidator])
     uri = fields.StringField(required=True, validators=[URIValidator])
     sdp = fields.StringField(required=True)
 
 
 class SessionAnswerRequest(SessionRequestBase):
     sylkrtc = DefaultValueField('session-answer')
     sdp = fields.StringField(required=True)
 
 
 class SessionTrickleRequest(SessionRequestBase):
     sylkrtc = DefaultValueField('session-trickle')
     candidates = fields.ListField([ICECandidate])
 
 
 class SessionTerminateRequest(SessionRequestBase):
     sylkrtc = DefaultValueField('session-terminate')
 
 
 # VideoRoom models
 
 class VideoRoomRequestBase(SylkRTCRequestBase):
     session = fields.StringField(required=True)
 
 
 class VideoRoomJoinRequest(VideoRoomRequestBase):
     sylkrtc = DefaultValueField('videoroom-join')
     account = fields.StringField(required=True, validators=[URIValidator])
     uri = fields.StringField(required=True, validators=[URIValidator])
     sdp = fields.StringField(required=True)
 
 
 class VideoRoomControlTrickleRequest(models.Base):
     # ID for the subscriber session, if specified, otherwise the publisher is considered
     session = fields.StringField(required=False)
     candidates = fields.ListField([ICECandidate])
 
 
 class VideoRoomControlUpdateRequest(models.Base):
     audio = fields.BoolField(required=False)
     video = fields.BoolField(required=False)
     bitrate = fields.IntField(required=False)
 
 
 class VideoRoomControlFeedAttachRequest(models.Base):
     session = fields.StringField(required=True)
     publisher = fields.StringField(required=True)
 
 
 class VideoRoomControlFeedAnswerRequest(models.Base):
     session = fields.StringField(required=True)
     sdp = fields.StringField(required=True)
 
 
 class VideoRoomControlFeedDetachRequest(models.Base):
     session = fields.StringField(required=True)
 
 
 class VideoRoomControlInviteParticipantsRequest(models.Base):
     participants = fields.ListField([str, unicode], validators=[URIListValidator])
 
 
 class VideoRoomControlRequest(VideoRoomRequestBase):
     sylkrtc = DefaultValueField('videoroom-ctl')
     option = fields.StringField(required=True, validators=[OptionsValidator(['trickle', 'update', 'feed-attach', 'feed-answer', 'feed-detach', 'invite-participants'])])
 
     # all other options should have optional fields below, and the application needs to do a little validation
     trickle = fields.EmbeddedField(VideoRoomControlTrickleRequest, required=False)
     update = fields.EmbeddedField(VideoRoomControlUpdateRequest, required=False)
     feed_attach = fields.EmbeddedField(VideoRoomControlFeedAttachRequest, required=False)
     feed_answer = fields.EmbeddedField(VideoRoomControlFeedAnswerRequest, required=False)
     feed_detach = fields.EmbeddedField(VideoRoomControlFeedDetachRequest, required=False)
     invite_participants = fields.EmbeddedField(VideoRoomControlInviteParticipantsRequest, required=False)
 
 
 class VideoRoomTerminateRequest(VideoRoomRequestBase):
     sylkrtc = DefaultValueField('videoroom-terminate')