diff --git a/demo/Dockerfile b/demo/Dockerfile
index 40dffe11f..6eaf4c8c5 100644
--- a/demo/Dockerfile
+++ b/demo/Dockerfile
@@ -17,6 +17,7 @@ COPY demo/alertmanager.yaml /etc/alertmanager.yaml
 COPY demo/generator.py /generator.py
 COPY --from=go-builder /go/src/github.com/prymitive/karma/karma /karma
 COPY demo/karma.yaml /etc/karma.yaml
+COPY demo/custom.js /custom.js
 RUN adduser -D karma
 USER karma
 CMD supervisord --nodaemon --configuration /etc/supervisord.conf
diff --git a/demo/custom.js b/demo/custom.js
new file mode 100644
index 000000000..d764ca96f
--- /dev/null
+++ b/demo/custom.js
@@ -0,0 +1,23 @@
+// https://developers.google.com/analytics/devguides/collection/analyticsjs/
+(function(i, s, o, g, r, a, m) {
+  i["GoogleAnalyticsObject"] = r;
+  (i[r] =
+    i[r] ||
+    function() {
+      (i[r].q = i[r].q || []).push(arguments);
+    }),
+    (i[r].l = 1 * new Date());
+  (a = s.createElement(o)), (m = s.getElementsByTagName(o)[0]);
+  a.async = 1;
+  a.src = g;
+  m.parentNode.insertBefore(a, m);
+})(
+  window,
+  document,
+  "script",
+  "https://www.google-analytics.com/analytics.js",
+  "ga"
+);
+
+ga("create", "UA-128338979-1", "auto");
+ga("send", "pageview");
diff --git a/demo/karma.yaml b/demo/karma.yaml
index 246ea8841..145db0d96 100644
--- a/demo/karma.yaml
+++ b/demo/karma.yaml
@@ -8,6 +8,8 @@ alertmanager:
 annotations:
   hidden:
     - help
+custom:
+  js: /custom.js
 filters:
   default:
     - "@receiver=by-cluster-service"