diff --git a/index.js b/index.js
index 8441b26..df1fe8e 100644
--- a/index.js
+++ b/index.js
@@ -73,7 +73,7 @@ app.delete('/api/notes/:id', (request, response) => {
   response.status(204).end()
 })
 
-const PORT = 3001
+const PORT = process.env.PORT || 3001
 app.listen(PORT, () => {
   console.log(`Server running on port ${PORT}`)
 })