diff --git a/docs/exposing-prometheus-alertmanager-grafana-ingress.md b/docs/exposing-prometheus-alertmanager-grafana-ingress.md
index 007dc641fa028773a369f703331e326dc5c84d62..7fb2d4f6a8d4c8cb096f9a8978c48962b46b58b3 100644
--- a/docs/exposing-prometheus-alertmanager-grafana-ingress.md
+++ b/docs/exposing-prometheus-alertmanager-grafana-ingress.md
@@ -43,7 +43,7 @@ local kp =
     prometheus+:: {
       prometheus+: {
         spec+: {
-          externalURL: 'http://prometheus.example.com',
+          externalUrl: 'http://prometheus.example.com',
         },
       },
     },