diff --git a/requirements.txt b/requirements.txt
index 76b1d15a7b..4179e1b002 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -22,3 +22,4 @@ mock==2.0.0
 timeout-decorator==0.3.2
 raven==5.23.0
 demjson==2.2.4
+greenlet==0.4.9