diff --git a/.on-save.json b/.on-save.json
new file mode 100644
index 0000000..68ab8ff
--- /dev/null
+++ b/.on-save.json
@@ -0,0 +1,6 @@
+[
+  {
+    "files": "**/*.{ex,exs}",
+    "command": "mix format ${srcFile}"
+  }
+]