diff --git a/src/backend/services/runtimeConfig.ts b/src/backend/services/runtimeConfig.ts
index 37e23db..e0be560 100644
--- a/src/backend/services/runtimeConfig.ts
+++ b/src/backend/services/runtimeConfig.ts
@@ -32,7 +32,7 @@ export function generateRuntimeConfig(
 
     // Generate env.js content
     const envConfig = {
-      basePath: basePath || '/',
+      BASE_PATH: basePath || '/',
       FRONTEND_API_KEY: config.apiKeys.frontend,
     };
 
diff --git a/src/frontend/public/env.js b/src/frontend/public/env.js
index d57ec5d..e2501bb 100644
--- a/src/frontend/public/env.js
+++ b/src/frontend/public/env.js
@@ -2,5 +2,6 @@
 // DO NOT EDIT - This file is automatically generated
 // eslint-disable-next-line no-undef
 window.env = {
-  "basePath": "/"
+  "BASE_PATH": "/",
+  "FRONTEND_API_KEY": "frontend-dev-key"
 };
diff --git a/src/frontend/src/main.tsx b/src/frontend/src/main.tsx
index 962f293..5146b18 100644
--- a/src/frontend/src/main.tsx
+++ b/src/frontend/src/main.tsx
@@ -3,17 +3,7 @@ import ReactDOM from 'react-dom/client';
 import { BrowserRouter } from 'react-router-dom';
 import App from './App.tsx';
 
-// Runtime config loaded from env.js (generated by backend at startup)
-declare global {
-  interface Window {
-    env?: {
-      basePath?: string;
-      FRONTEND_API_KEY: string;
-    };
-  }
-}
-
-const basename = window.env?.basePath || '/';
+const basename = window.env.BASE_PATH || '/';
 
 ReactDOM.createRoot(document.getElementById('root')!).render(
   <React.StrictMode>
diff --git a/src/frontend/src/types/globals.d.ts b/src/frontend/src/types/globals.d.ts
new file mode 100644
index 0000000..374e990
--- /dev/null
+++ b/src/frontend/src/types/globals.d.ts
@@ -0,0 +1,20 @@
+/**
+ * Global type declarations for the Bitip frontend application
+ * This file contains ambient declarations for global objects and runtime configuration
+ */
+
+/**
+ * Runtime configuration loaded from env.js
+ * Generated by backend at startup and injected into window object
+ */
+declare global {
+  interface Window {
+    env: {
+      BASE_PATH: string;
+      FRONTEND_API_KEY: string;
+    };
+  }
+}
+
+// This export makes this file a module, which is required for global augmentation
+export {};