diff --git a/.arcconfig b/.arcconfig
new file mode 100644
index 0000000000..8c3ac6b95c
--- /dev/null
+++ b/.arcconfig
@@ -0,0 +1,5 @@
+{
+  "phabricator.uri" : "https://phabricator.services.mozilla.com/",
+  "repository.callsign": "NSS",
+  "history.immutable": false
+}