diff --git a/spaceapi/state.py b/spaceapi/state.py
--- a/spaceapi/state.py
+++ b/spaceapi/state.py
@@ -9,12 +9,8 @@ from .auth import httpauth
 
 state_views = Blueprint('state', __name__)
 
-ALLOWED_STATE_KEYS = {
-    'open': bool,
-    'lastchange': int,
-    'trigger_person': str,
-    'message': str
-}
+ALLOWED_STATE_KEYS = frozenset(('open', 'lastchange',
+                                'trigger_person', 'message'))
 
 
 @state_views.route('/set/<key>', methods=['POST'])