diff --git a/builder/modal-builder/README.md b/builder/modal-builder/README.md
index c68c46e..24f7e6f 100644
--- a/builder/modal-builder/README.md
+++ b/builder/modal-builder/README.md
@@ -16,6 +16,7 @@ docker build -t bennykok/comfydeploy-builder:dev . && docker run --env-file .env
 ```
 
 ## Before Deploy to Fly.io
+there are 2 `toml` files one is for `preview` and the other is for `prod`
 ## Fly.io installation
 
 ### Mac/Liunx
@@ -54,4 +55,4 @@ fly launch
 if not, run this instead
 ```
 fly deploy
-```
\ No newline at end of file
+```