diff --git a/src/routes/api.js b/src/routes/api.js
index 40b7300..969a1aa 100644
--- a/src/routes/api.js
+++ b/src/routes/api.js
@@ -34,7 +34,7 @@ import apiRouter2 from '../api/v2/index.js'
 
 const router = express.Router()
 
-if (process.env.ENABLE_MAIN_MODULE === 'true') {
+if ((process.env.ENABLE_MAIN_MODULE ?? 'true') === 'true') {
   router.use('/0', apiRouter0)
 }
 router.use('/1', apiRouter1)