diff --git a/docker/Dockerfile.io b/docker/Dockerfile.io
index 12c17806..974f434d 100644
--- a/docker/Dockerfile.io
+++ b/docker/Dockerfile.io
@@ -41,6 +41,7 @@ ENV cloudcmd_terminal=true
 ENV cloudcmd_terminal_path=gritty
 ENV cloudcmd_open=false
 ENV PATH=node_modules/.bin:$PATH
+ENV PORT=1337
 
 EXPOSE 1337