diff --git a/README.md b/README.md
index 4b3e027..1960e39 100644
--- a/README.md
+++ b/README.md
@@ -233,6 +233,8 @@ For an overview of known relays, see [A sorted list of ActivityPub relays for Ma
 
 * :heavy_check_mark: [**activitypub-mock**](https://gitlab.com/evanp/activitypub-mock): A mock ActivityPub server to use in testing code `Apache-2.0, Javascript`
 
+* [**APDebug**](https://codeberg.org/samuelroland/apdebug) ([Fedi account](https://fosstodon.org/@samuelroland)): A set of tools to debug ActivityPub requests. You can inspect requests, see the flow in real time, run arbitrary requests with HTTP signature handled for you. `AGPL-3.0, PHP`
+
 * [**dfk-ap**](https://glitch.com/edit/#!/dfk-ap?path=README.md%3A1%3A0) ([site](https://tinysubversions.com/notes/activitypub-tool/)): A small ActivityPub debugging server on Glitch `MIT, Javascript`
 
 * :heavy_check_mark: [**FediDB**](https://github.com/fedidb/fedidb-ce) ([site](https://fedidb.org/about), [Fedi account](https://mastodon.social/@dansup)): A suite of tools for AP devs to help make it easier to test and validate your implementation with existing implementations like Mastodon, PeerTube, Pixelfed and Pleroma `AGPL-3.0, PHP`