diff --git a/README.md b/README.md
index 4183f98a..82a33d73 100644
--- a/README.md
+++ b/README.md
@@ -68,7 +68,7 @@ The page will auto-refresh everytime a change is made.
 
 #### Usage with frontend
 
-If you use this service through local frontend, you're ready to go - frontend will pass your authorization token directly to the app.
+If you use this service through local frontend, you will need to add `PDF_SERVICE_URL=http://localhost:3002` line to `.env`. You're ready to go - frontend will pass your authorization token directly to the app.
 
 However this is not practical to develop, you should only use it to debug the
 bridge between the two services.