diff --git a/app/main.py b/app/main.py
index 6aded37..89ab42a 100644
--- a/app/main.py
+++ b/app/main.py
@@ -50,6 +50,11 @@ from app.core.heartbeat_monitor_worker import (
     stop_heartbeat_monitor,
 )
 from app.core.logging import setup_logging
+from app.core.observe import RequestMetricsMiddleware
+from app.core.observe_worker import (
+    start_observe_worker,
+    stop_observe_worker,
+)
 from app.core.pricebot_client import aclose_pricebot_client, get_pricebot_client
 from app.core.withdraw_reconcile_worker import (
     start_withdraw_reconcile_worker,
@@ -74,12 +79,14 @@ async def lifespan(_: FastAPI) -> AsyncIterator[None]:
     reconcile_task = start_withdraw_reconcile_worker()
     heartbeat_task = start_heartbeat_monitor()
     daily_exchange_task = start_daily_exchange_worker()
+    observe_task = start_observe_worker()
     try:
         yield
     finally:
         await stop_heartbeat_monitor(heartbeat_task)
         await stop_withdraw_reconcile_worker(reconcile_task)
         await stop_daily_exchange_worker(daily_exchange_task)
+        await stop_observe_worker(observe_task)
         await aclose_pricebot_client()
         logger.info("shutting down")
 
@@ -101,6 +108,9 @@ if settings.cors_origins_list:
         allow_headers=["*"],
     )
 
+# 接口指标埋点(放在 CORS 之后 = 最外层:测到含 CORS 的完整耗时)。未配置观测时中间件自 no-op。
+app.add_middleware(RequestMetricsMiddleware)
+
 
 @app.get("/health", tags=["meta"])
 def health() -> dict[str, str]:
diff --git a/tests/test_observe.py b/tests/test_observe.py
index 0816c7a..3ca966b 100644
--- a/tests/test_observe.py
+++ b/tests/test_observe.py
@@ -225,3 +225,10 @@ async def test_stop_flushes_remaining_and_closes_client(monkeypatch):
 
     assert b'"n"' in posted["body"]        # 关停时把剩余事件发了出去
     assert observe_worker._client is None  # client 已关闭并置空
+
+
+def test_app_has_metrics_middleware():
+    from app.main import app
+
+    names = [m.cls.__name__ for m in app.user_middleware]
+    assert "RequestMetricsMiddleware" in names