diff --git a/nb2kg/nb2kg/handlers.py b/nb2kg/nb2kg/handlers.py
index 36b8e41..13a7955 100644
--- a/nb2kg/nb2kg/handlers.py
+++ b/nb2kg/nb2kg/handlers.py
@@ -112,7 +112,7 @@ def __init__(self):
     @gen.coroutine
     def _connect(self, kernel_id):
         ws_url = url_path_join(
-            KG_URL.replace('http', 'ws'), 
+            os.getenv('KG_WS_URL', KG_URL.replace('http', 'ws')),
             '/api/kernels', 
             url_escape(kernel_id),
             'channels'