diff --git a/apps/api/src/index.ts b/apps/api/src/index.ts
index 4cd8748..b49262d 100644
--- a/apps/api/src/index.ts
+++ b/apps/api/src/index.ts
@@ -13,7 +13,7 @@ import { oidcAuthMiddleware, processOAuthCallback } from './auth/middleware.js';
 import { devAuthBypass } from './auth/devBypass.js';
 import { persistSessionCookie } from './auth/persistSessionCookie.js';
 import { startBrokerPoller } from './broker/poller.js';
-import { startOutboxWorker } from './broker/outboxWorker.js';
+import { startOutboxWorker, initOutboxTrigger } from './broker/outboxWorker.js';
 import { startReminderScheduler } from './broker/reminderScheduler.js';
 import webpush from 'web-push';
 
@@ -136,6 +136,7 @@ if (isMainModule()) {
   startBrokerPoller();
   // Drain the D-05 outbox every 15s: dispatches pending CalDAV writes to Fastmail.
   startOutboxWorker();
+  initOutboxTrigger(); // subscribe drain signal listener (D-01)
   // Start the 1-min reminder scan for shared timed events starting in ~15 min (NOTIF-01).
   // VAPID must be configured (above) before this starts or push sends will fail.
   startReminderScheduler();