diff --git a/formate.toml b/formate.toml
index 7a96ca04..d69adeb3 100644
--- a/formate.toml
+++ b/formate.toml
@@ -35,6 +35,7 @@ known_third_party = [
     "apeye",
     "appdirs",
     "attrs",
+    "betamax",
     "bump2version",
     "check_wheel_contents",
     "click",