Index: src/routes/posts.js
===================================================================
--- src/routes/posts.js	(revision 834bcc3c41c52321679550863b74ca035538659f)
+++ src/routes/posts.js	(revision dd1028af6e9c6676e6c93734784524e86e57a3d6)
@@ -19,4 +19,5 @@
 import { audioUrl } from '../services/AudioStreamService.js';
 import { toWebp } from '../services/ImageWebpService.js';
+import ActivityPubService from '../services/ActivityPubService.js';
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url));
@@ -230,4 +231,12 @@
       ).run(HtmlSanitizerService.toPlainText(cleanContent), title || '', req.session.user.username, postId);
     } catch (e) { /* FTS index issues are non-fatal */ }
+
+    // ActivityPub: federate a freshly published public post to followers.
+    if (!fanOnly) {
+      ActivityPubService.deliverCreate(site, {
+        id: postId, slug: finalSlug, title: title || finalSlug,
+        content: cleanContent, published_at: publishedAt, created_at: now,
+      }).catch(() => { /* best-effort */ });
+    }
   }