diff --git a/docs/alpha-ref.json b/docs/alpha-ref.json
new file mode 100644
index 00000000..8cd3d839
--- /dev/null
+++ b/docs/alpha-ref.json
@@ -0,0 +1,3 @@
+{
+  "appref": "Microsoft/pxt-microbit-built#HEAD"
+}