diff --git a/app/core/celery_config.py b/app/core/celery_config.py
index 53adb750..58214124 100644
--- a/app/core/celery_config.py
+++ b/app/core/celery_config.py
@@ -72,6 +72,12 @@ celery_app = Celery(
     include=get_all_task_modules(),
 )
 
+# Mark this as the default app so @shared_task decorators in module task
+# files bind to it. Otherwise they fall back to Celery's built-in default,
+# which uses amqp://localhost// and silently fails with "Connection refused"
+# at .delay() time when no RabbitMQ is deployed.
+celery_app.set_default()
+
 # =============================================================================
 # CELERY CONFIGURATION
 # =============================================================================
diff --git a/main.py b/main.py
index cad60d4a..51e5d76b 100644
--- a/main.py
+++ b/main.py
@@ -32,6 +32,16 @@ from sqlalchemy import text
 from sqlalchemy.orm import Session
 from uvicorn.middleware.proxy_headers import ProxyHeadersMiddleware
 
+# Bootstrap Celery default app BEFORE importing api_router, which
+# transitively imports loyalty/billing/etc. task modules. Their @shared_task
+# decorators bind at import time to whatever Celery considers the current
+# default app — without our app.set_default() running first, they fall back
+# to Celery's built-in default (amqp://localhost//) and .delay() raises
+# ConnectionRefusedError at runtime. The isort: split below stops ruff from
+# alphabetically reordering this back behind api_router.
+from app.core import celery_config  # noqa: F401  # side-effect: set_default()
+
+# isort: split
 from app.api.main import api_router
 from app.core.config import settings