diff --git a/serve.py b/serve.py
index bbd1120..eb9b51c 100644
--- a/serve.py
+++ b/serve.py
@@ -12,4 +12,4 @@ def send_my_headers(self):
                 self.send_header("Cross-Origin-Opener-Policy", "same-origin")
 
 if __name__ == '__main__':
-        server.test(HandlerClass=MyHTTPRequestHandler, port=80)
+        server.test(HandlerClass=MyHTTPRequestHandler, port=os.environ.get('PORT', 8080))