diff --git a/.changeset/silent-chairs-smoke.md b/.changeset/silent-chairs-smoke.md
new file mode 100644
index 0000000000..bfd3a4d7cb
--- /dev/null
+++ b/.changeset/silent-chairs-smoke.md
@@ -0,0 +1,5 @@
+---
+'@backstage/frontend-app-api': patch
+---
+
+Fix for app node output IDs not being serialized correctly.
diff --git a/packages/frontend-app-api/src/tree/resolveAppTree.ts b/packages/frontend-app-api/src/tree/resolveAppTree.ts
index 9fda8e0f6a..e1665a01fd 100644
--- a/packages/frontend-app-api/src/tree/resolveAppTree.ts
+++ b/packages/frontend-app-api/src/tree/resolveAppTree.ts
@@ -65,7 +65,7 @@ class SerializableAppNode implements AppNode {
     const dataRefs = this.instance && [...this.instance.getDataRefs()];
     const out =
       dataRefs && dataRefs.length > 0
-        ? ` out=[${[...dataRefs.keys()].join(', ')}]`
+        ? ` out=[${[...dataRefs].map(r => r.id).join(', ')}]`
         : '';
 
     if (this.edges.attachments.size === 0) {