diff --git a/requirements.txt b/requirements.txt
index 9b57ccc..c536c16 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,4 +7,5 @@ pytest-flakes==4.0.0
 # because of pip bug https://github.com/pypa/pip/issues/4780
 aiohttp==3.5.4
 certifi==2019.3.9
+types-certifi==2020.4.0
 psutil==5.6.6; sys_platform == 'darwin'