diff --git a/swh/web/api/throttling.py b/swh/web/api/throttling.py
--- a/swh/web/api/throttling.py
+++ b/swh/web/api/throttling.py
@@ -61,6 +61,8 @@
     def __init__(self):
         super().__init__()
         self.exempted_networks = None
+        self.num_requests = 0
+        self.duration = 0
 
     def get_exempted_networks(
         self, scope_name: str