diff --git a/chat-app/build.ts b/chat-app/build.ts
index ba4f5f8..42173bc 100644
--- a/chat-app/build.ts
+++ b/chat-app/build.ts
@@ -15,7 +15,7 @@ async function main() {
     ...config,
     verbose: true,
     define: {
-      'Bun.env.APP_URL': Bun.env.APP_URL,
+      'Bun.env.APP_URL': `"${Bun.env.APP_URL}"`,
     }
   });