diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..f05565b
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,4 @@
+[tool.pytest.ini_options]
+markers = [
+    "optional: marks tests as optional (deselect with '-m \"not optional\"')",
+]
\ No newline at end of file