diff --git a/instance-monitoring-sites.md b/instance-monitoring-sites.md
index fafe71f..d2ab612 100644
--- a/instance-monitoring-sites.md
+++ b/instance-monitoring-sites.md
@@ -17,6 +17,7 @@
 * [join-lemmy.org/instances](https://join-lemmy.org/instances) - Lemmy only
 * [lemmymap.feddit.de](https://lemmymap.feddit.de) - Lemmy only
 * [joinbookwyrm.com/instances](https://joinbookwyrm.com/instances) - Bookwyrm only
+* [mastodon.help/instances](https://mastodon.help/instances/en) - Mastodon only
 
 #### Other
 * [kumu.io/wakest/fediverse](https://kumu.io/wakest/fediverse) - visualization