diff --git a/requirements.txt b/requirements.txt
index c4c7fcc..6908527 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -21,3 +21,4 @@
 PrettyTable>=0.7.1 # BSD
 urllib3>=1.21.1 # MIT
 debtcollector>=1.2.0 # Apache-2.0
+tenacity>=4.4.0 # Apache-2.0