diff --git a/lib/federation-bridge.js b/lib/federation-bridge.js
index 1295745..5b39051 100644
--- a/lib/federation-bridge.js
+++ b/lib/federation-bridge.js
@@ -89,6 +89,12 @@ async function sendFedifyResponse(res, response, request) {
       if (json.attachment && !Array.isArray(json.attachment)) {
         json.attachment = [json.attachment];
       }
+      // WORKAROUND: Fedify serializes endpoints with "type": "as:Endpoints"
+      // which is not a valid AS2 type. The endpoints object should be a plain
+      // object with just sharedInbox/proxyUrl etc. Strip the invalid type.
+      if (json.endpoints && json.endpoints.type) {
+        delete json.endpoints.type;
+      }
       const patched = JSON.stringify(json);
       res.setHeader("content-length", Buffer.byteLength(patched));
       res.end(patched);