diff --git a/index.ts b/index.ts
index b0db0b0..b8b368c 100644
--- a/index.ts
+++ b/index.ts
@@ -67,7 +67,7 @@ const server = http.createServer(async (req, res) => {
 
 // Auto run
 if (require.main === module) {
-  server.listen(3000)
+  server.listen(process.env.PORT || 3000)
 }
 
 process.on('unhandledRejection', e => {