diff --git a/packages/react-email/src/cli/utils/preview/start-dev-server.ts b/packages/react-email/src/cli/utils/preview/start-dev-server.ts
index fbea884815..454ae1de9a 100644
--- a/packages/react-email/src/cli/utils/preview/start-dev-server.ts
+++ b/packages/react-email/src/cli/utils/preview/start-dev-server.ts
@@ -120,7 +120,9 @@ export const startDevServer = async (
   // this is the most reliable way of communicating these paths through
   process.env = {
     NODE_ENV: 'development',
-    ...process.env,
+    ...(process.env as Omit<NodeJS.ProcessEnv, 'NODE_ENV'> & {
+      NODE_ENV?: NodeJS.ProcessEnv['NODE_ENV'];
+    }),
     ...getEnvVariablesForPreviewApp(
       // If we don't do normalization here, stuff like https://github.com/resend/react-email/issues/1354 happens.
       path.normalize(emailsDirRelativePath),