diff --git a/README.md b/README.md
index 70e492b..49c0796 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,8 @@ We encourage you to run your own thingproxy server with this source code, but fr
 
 http://thingproxy.freeboard.io and https://thingproxy.freeboard.io
 
+(hosted instances only work from localhost domains for development - deploy your own for use from an internet domain)
+
 ### why?
 
 Dashboards created with freeboard normally access APIs directly from ajax calls from javascript. Many API providers do not provide the proper CORS headers, or don't support HTTPS— thingproxy is provided to overcome these limitations.