diff --git a/site/posts/2019-09-22-activitypub-resources.md b/site/posts/2019-09-22-activitypub-resources.md
index f17a667..f6efb7d 100644
--- a/site/posts/2019-09-22-activitypub-resources.md
+++ b/site/posts/2019-09-22-activitypub-resources.md
@@ -34,4 +34,5 @@ This post was last updated on Oct 10, 2019.
 ### Other
 - For actually testing federation, [ngrok](https://ngrok.com/) is very useful for testing your implementations against others. It creates a tunnel from your local machine to a public domain with HTTPS already setup. Because your code is still running locally, you have access to all your usual debugging tools and can iterate rapidly.
 - Testing against other implementations running locally (be it on your machine or inside a VM/container) lets you access debug logs and see what the other server is actually receiving, which can be quite useful.
+- Darius Kazemi also wrote [an application](https://tinysubversions.com/notes/activitypub-tool/) that lets you send ActivityPub objects directly to other servers, which is useful for testing your application against outside data without polluting other people's instances.
 - Ted Unangst also has his own [compilation of AP-related links](https://flak.tedunangst.com/post/ActivityPub-as-it-has-been-understood).