diff --git a/ask/__init__.py b/ask/__init__.py
index 44652c0..112f0e2 100644
--- a/ask/__init__.py
+++ b/ask/__init__.py
@@ -1,4 +1,5 @@
 from . import alexa_io
+from alexa_io import InvalidAppIdException
 
 ''' 
 Setting up some nice abstractions around good object oritented code.
diff --git a/ask/alexa_io.py b/ask/alexa_io.py
index a96688c..7a4230c 100644
--- a/ask/alexa_io.py
+++ b/ask/alexa_io.py
@@ -13,15 +13,20 @@
 }"""
 
 
+class InvalidAppIdException(Exception):
+    pass
+
+
 class Request(object):
     """
     Simple wrapper around the JSON request
     received by the module
     """
-    def __init__(self, request_dict, metadata=None):
+    def __init__(self, request_dict, metadata=None, supported_app_ids=None):
         self.request = request_dict
         self.metadata = metadata or {}
         self.session = self.request.get('session', {}).get('attributes', {})
+        self.supported_app_ids = supported_app_ids
         if self.intent_name():
             self.slots = self.get_slot_map()
 
@@ -50,6 +55,19 @@ def access_token(self):
     def session_id(self):
         return self.request["session"]["sessionId"]
 
+    def application_id(self):
+        try:
+            return self.request['session']['application']['applicationId']
+        except:
+            return None
+
+    def has_valid_app_id(self):
+        if not self.supported_app_ids:
+            return True
+        if not self.application_id():
+            return False
+        return self.application_id() in self.supported_app_ids
+
     def get_slot_value(self, slot_name):
         try:
             return self.request["request"]["intent"]["slots"][slot_name]["value"]
@@ -192,11 +210,18 @@ def _handler(func):
 
         return _handler
 
-    def route_request(self, request_json, metadata=None):
+    def route_request(self, request_json, metadata=None, app_ids=None):
 
         ''' Route the request object to the right handler function '''
         request = Request(request_json)
+        request.supported_app_ids = app_ids
         request.metadata = metadata
+
+        # before we do anything, lets verify the application id
+        # if app_ids is not passed in, verification does not occur
+        if not request.has_valid_app_id():
+            raise InvalidAppIdException('Invalid ApplicationId: %s' % request.application_id())
+
         # add reprompt handler or some such for default?
         handler_fn = self._handlers[self._default] # Set default handling for noisy requests
 
diff --git a/tests/test_alexa.py b/tests/test_alexa.py
index 2b6e944..bed5150 100644
--- a/tests/test_alexa.py
+++ b/tests/test_alexa.py
@@ -1,4 +1,4 @@
-from nose.tools import assert_equal, assert_dict_equal, assert_true
+from nose.tools import assert_equal, assert_dict_equal, assert_true, raises
 
 from .context import ask
 from .fixtures.requests import (TEST_SESSION_ENDED_REQUEST, TEST_LAUNCH_REQUEST,
@@ -83,3 +83,14 @@ def test_routes_to_request_handler(self):
 
         response = ask.alexa.route_request(req_json)
         assert_true(response['request_handler_called'])
+
+    @raises(ask.InvalidAppIdException)
+    def test_raises_invalid_app_id(self):
+        req_json = TEST_INTENT_REQUEST
+        ids = ['supported_id', 'another_bad_id']
+        ask.alexa.route_request(req_json, app_ids=ids)
+
+    def test_valid_app_id(self):
+        req_json = TEST_INTENT_REQUEST
+        ids = ['amzn1.echo-sdk-ams.app.000000-d0ed-0000-ad00-000000d00ebe']
+        ask.alexa.route_request(req_json, app_ids=ids)
diff --git a/tests/test_request.py b/tests/test_request.py
index 58d4c03..ff7fcac 100644
--- a/tests/test_request.py
+++ b/tests/test_request.py
@@ -57,6 +57,27 @@ def test_request_returns_session_id(self):
 
         assert_equal(session_id, "SessionId.d461672c-2997-4d9d-9a8c-a67834acb9aa")
 
+    def test_request_returns_application_id(self):
+        application_id = self.example.application_id()
+
+        assert_equal(application_id, "amzn1.echo-sdk-ams.app.a306b3a3-3331-43c1-87bd-87d29d16fac8")
+
+    def test_request_has_valid_application_id_empty_app_ids(self):
+        assert_true(self.example.has_valid_app_id())
+
+    def test_request_has_valid_application_id(self):
+        self.example.supported_app_ids = ['amzn1.echo-sdk-ams.app.a306b3a3-3331-43c1-87bd-87d29d16fac8']
+
+        assert_true(self.example.has_valid_app_id())
+
+    def test_request_has_invalid_application_id(self):
+        def app_id_mock():
+            return 'bad_app_id'
+
+        self.example.supported_app_ids = ['amzn1.echo-sdk-ams.app.a306b3a3-3331-43c1-87bd-87d29d16fac8']
+        self.example.application_id = app_id_mock
+        assert_false(self.example.has_valid_app_id())
+
     def test_request_returns_slot_value(self):
         val1 = self.example.get_slot_value("example1")
         val2 = self.example.get_slot_value("example2")