diff --git a/requirements.txt b/requirements.txt
index e367c1b8..8c0e0f13 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -17,3 +17,4 @@ typing-extensions==3.7.4.1 ; python_version < '3.8'
 urllib3==1.25.8
 werkzeug==1.0.0
 gevent==1.4.0
+greenlet==0.4.15