diff --git a/packages/engine-cli/src/create-environments-build-configuration.ts b/packages/engine-cli/src/create-environments-build-configuration.ts
index 193115b58..a27eada88 100644
--- a/packages/engine-cli/src/create-environments-build-configuration.ts
+++ b/packages/engine-cli/src/create-environments-build-configuration.ts
@@ -40,7 +40,11 @@ export function createBuildConfiguration(options: CreateBuildConfigOptions) {
     const commonConfig = {
         target: 'es2020',
         bundle: true,
-        format: 'esm',
+        /*
+            using iife here because esm makes debugging very slow to pickup variables in scope.
+            if one want to change this to esm, make sure that some bundle splitting is happening.
+        */
+        format: 'iife',
         publicPath,
         metafile: true,
         sourcemap: true,