diff --git a/synapse/handlers/__init__.py b/synapse/handlers/__init__.py
index fe071a4bc..96a9b143c 100644
--- a/synapse/handlers/__init__.py
+++ b/synapse/handlers/__init__.py
@@ -26,6 +26,7 @@ from .presence import PresenceHandler
 from .directory import DirectoryHandler
 from .typing import TypingNotificationHandler
 from .admin import AdminHandler
+from .appservice import ApplicationServicesHandler
 
 
 class Handlers(object):
@@ -51,3 +52,4 @@ class Handlers(object):
         self.directory_handler = DirectoryHandler(hs)
         self.typing_notification_handler = TypingNotificationHandler(hs)
         self.admin_handler = AdminHandler(hs)
+        self.appservice_handler = ApplicationServicesHandler(hs)
diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
new file mode 100644
index 000000000..55a653476
--- /dev/null
+++ b/synapse/handlers/appservice.py
@@ -0,0 +1,49 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from twisted.internet import defer
+
+from ._base import BaseHandler
+from synapse.api.errors import StoreError, SynapseError
+
+import logging
+
+
+logger = logging.getLogger(__name__)
+
+
+class ApplicationServicesHandler(BaseHandler):
+
+    def __init__(self, hs):
+        super(ApplicationServicesHandler, self).__init__(hs)
+
+    @defer.inlineCallbacks
+    def register(self, base_url, token, namespaces):
+        # check the token is recognised
+        try:
+            app_service = yield self.store.get_app_service(token)
+            if not app_service:
+                raise StoreError
+        except StoreError:
+            raise SynapseError(
+                403, "Unrecognised application services token. "
+                "Consult the home server admin."
+            )
+
+        # update AS entry with base URL
+
+        # store namespaces for this AS
+
+        defer.returnValue("not_implemented_yet")
diff --git a/synapse/rest/appservice/v1/base.py b/synapse/rest/appservice/v1/base.py
index 46c9a444c..65d5bcf9b 100644
--- a/synapse/rest/appservice/v1/base.py
+++ b/synapse/rest/appservice/v1/base.py
@@ -44,4 +44,5 @@ class AppServiceRestServlet(RestServlet):
     """
 
     def __init__(self, hs):
-        self.hs = hs
\ No newline at end of file
+        self.hs = hs
+        self.handler = hs.get_handlers().appservice_handler
diff --git a/synapse/rest/appservice/v1/register.py b/synapse/rest/appservice/v1/register.py
index 779447ac6..142f09a63 100644
--- a/synapse/rest/appservice/v1/register.py
+++ b/synapse/rest/appservice/v1/register.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 """This module contains REST servlets to do with registration: /register"""
+from twisted.internet import defer
 
 from base import AppServiceRestServlet, as_path_pattern
 from synapse.api.errors import CodeMessageException, SynapseError
@@ -30,6 +31,7 @@ class RegisterRestServlet(AppServiceRestServlet):
 
     PATTERN = as_path_pattern("/register$")
 
+    @defer.inlineCallbacks
     def on_POST(self, request):
         params = _parse_json(request)
 
@@ -56,9 +58,11 @@ class RegisterRestServlet(AppServiceRestServlet):
             self._parse_namespace(namespaces, params["namespaces"], "rooms")
             self._parse_namespace(namespaces, params["namespaces"], "aliases")
 
-        # TODO: pass to the appservice handler
+        hs_token = yield self.handler.register(as_url, as_token, namespaces)
 
-        raise CodeMessageException(500, "Not implemented.")
+        defer.returnValue({
+          "hs_token": hs_token
+        })
 
     def _parse_namespace(self, target_ns, origin_ns, ns):
         if ns not in target_ns or ns not in origin_ns:
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index 4beb951b9..9431c1a32 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -18,6 +18,7 @@ from twisted.internet import defer
 from synapse.util.logutils import log_function
 from synapse.api.constants import EventTypes
 
+from .appservice import ApplicationServiceStore
 from .directory import DirectoryStore
 from .feedback import FeedbackStore
 from .presence import PresenceStore
@@ -80,8 +81,8 @@ class DataStore(RoomMemberStore, RoomStore,
                 RegistrationStore, StreamStore, ProfileStore, FeedbackStore,
                 PresenceStore, TransactionStore,
                 DirectoryStore, KeyStore, StateStore, SignatureStore,
-                EventFederationStore,
-                MediaRepositoryStore,
+                EventFederationStore, MediaRepositoryStore,
+                ApplicationServiceStore
                 ):
 
     def __init__(self, hs):
diff --git a/synapse/storage/appservice.py b/synapse/storage/appservice.py
new file mode 100644
index 000000000..99f58b4c6
--- /dev/null
+++ b/synapse/storage/appservice.py
@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from twisted.internet import defer
+
+from synapse.api.errors import StoreError
+
+from ._base import SQLBaseStore
+
+
+class ApplicationServiceStore(SQLBaseStore):
+
+    def __init__(self, hs):
+        super(ApplicationServiceStore, self).__init__(hs)
+
+        self.clock = hs.get_clock()
+
+    @defer.inlineCallbacks
+    def get_app_service(self, as_token):
+        """Get the application service with the given token.
+
+        Args:
+            token (str): The application service token.
+        Raises:
+            StoreError if there was a problem retrieving this.
+        """
+        row = self._simple_select_one(
+            "application_services", {"token": as_token},
+            ["url", "token"]
+        )
+        if not row:
+            raise StoreError(400, "Bad application services token supplied.")
+        defer.returnValue(row)