diff --git a/requirements-common.txt b/requirements-common.txt
index 4f7309a6a..9e3e2816c 100644
--- a/requirements-common.txt
+++ b/requirements-common.txt
@@ -27,3 +27,6 @@ python-rapidjson==0.7.1
 
 # Notify systemd
 sdnotify==0.3.2
+
+# Api server
+flask==1.0.2