diff --git a/pytest.ini b/pytest.ini
index 9bf10c82..ac73d1e1 100644
--- a/pytest.ini
+++ b/pytest.ini
@@ -1,3 +1,6 @@
 [pytest]
 addopts = --flake8 --isort --cov radicale/ radicale/tests
 norecursedirs = dist .cache .git build *.egg-info .eggs venv
+
+[flake8]
+jobs=1