diff --git a/roles/fedmsg/base/files/relay-debug-loopback.py b/roles/fedmsg/base/files/relay-debug-loopback.py
new file mode 100644
index 0000000000..938cc8985d
--- /dev/null
+++ b/roles/fedmsg/base/files/relay-debug-loopback.py
@@ -0,0 +1,27 @@
+## WARNING ##
+# This file is a replacement for the *regular* relay.py file we ship to all
+# fedora infra prod/stg hosts.
+# If you are seeing this file on a host, that is because it has
+# fedmsg_debug_loopback set to 'true' in our ansible config.  That should be an
+# exceptional thing used only for debugging.
+#
+# Things to know:
+#
+# * No 'fedmsg-logger' statements on this host will make it to the real bus
+# * They will only be broadcast locally (on this box)
+# * No messages from the main fedmsg-relay on our bus will make it to this box.
+# * Other messages from persistent fedmsg services will make it here.
+#
+# You can use this to test services locally with 'fedmsg-dg-replay'.  Messages
+# rebroadcast by that command will be replayed locally, to only this host.
+
+config = dict(
+    endpoints={
+        "relay_outbound": [
+            "tcp://127.0.0.1:3999",
+        ],
+    },
+    relay_inbound=[
+        "tcp://127.0.0.1:9941",
+    ],
+)