diff --git a/stack-definition.yml b/stack-definition.yml
index 131e0be..c26bc04 100644
--- a/stack-definition.yml
+++ b/stack-definition.yml
@@ -6,7 +6,7 @@ services:
     volumes:
     - pchl:/app
     environment:
-    - PB_API:$PB_API
+    - PB_API:{{PB_API}}
     port:
     - 19080:19080
     deploy: