diff --git a/treefmt.toml b/treefmt.toml
new file mode 100644
index 0000000..2fb777a
--- /dev/null
+++ b/treefmt.toml
@@ -0,0 +1,3 @@
+[formatter.nixfmt-rfc-style]
+command = "nixfmt"
+includes = "*.nix"