diff --git a/README.md b/README.md
index 44cc43c..05b05d9 100644
--- a/README.md
+++ b/README.md
@@ -121,6 +121,7 @@ docker compose up -d
    # Start the frontend
    cd ../frontend
    npm run build
+   API_URL=http://localhost:8080 # Set the URL of the backend, default: http://localhost:8080
    pm2 restart pingvin-share-frontend
    ```