diff --git a/lib/backend.py b/lib/backend.py
index 3d4ef92..dc1f52c 100644
--- a/lib/backend.py
+++ b/lib/backend.py
@@ -171,7 +171,7 @@ class Backend:
         
         if self.metrics.model_metrics.wait_time > self.max_wait_time:
             self.metrics._request_reject(request_metrics)
-            return web.Response(status=500)
+            return web.Response(status=429)
 
         acquired = False
         try:
diff --git a/lib/metrics.py b/lib/metrics.py
index 40dcb9a..45f44f4 100644
--- a/lib/metrics.py
+++ b/lib/metrics.py
@@ -6,7 +6,7 @@ from asyncio import sleep
 from dataclasses import dataclass, asdict, field
 from functools import cache
 import asyncio
-import requests
+from aiohttp import ClientSession, ClientTimeout, TCPConnector, ClientResponseError
 
 from lib.data_types import AutoScalerData, SystemMetrics, ModelMetrics, RequestMetrics
 from typing import Awaitable, NoReturn, List
@@ -38,6 +38,20 @@ class Metrics:
     url: str = field(default_factory=get_url)
     system_metrics: SystemMetrics = field(default_factory=SystemMetrics.empty)
     model_metrics: ModelMetrics = field(default_factory=ModelMetrics.empty)
+    _session: ClientSession | None = field(default=None, init=False, repr=False)
+
+    async def http(self) -> ClientSession:
+        if self._session is None:
+            self._session = ClientSession(
+                timeout=ClientTimeout(total=10),
+                connector=TCPConnector(limit=8, limit_per_host=4, force_close=True, enable_cleanup_closed=True)
+            )
+        return self._session
+    
+    async def aclose(self) -> None:
+        if self._session is not None:
+            await self._session.close()
+            self._session = None
 
     def _request_start(self, request: RequestMetrics) -> None:
         """
@@ -101,7 +115,7 @@ class Metrics:
         while True:
             await sleep(DELETE_REQUESTS_INTERVAL)
             if len(self.model_metrics.requests_deleting) > 0:
-                self.__send_delete_requests_and_reset()
+                await self.__send_delete_requests_and_reset()
 
     async def _send_metrics_loop(self) -> Awaitable[NoReturn]:
         while True:
@@ -109,10 +123,10 @@ class Metrics:
             elapsed = time.time() - self.last_metric_update
             if self.system_metrics.model_is_loaded is False and elapsed >= 10:
                 log.debug(f"sending loading model metrics after {int(elapsed)}s wait")
-                self.__send_metrics_and_reset()
+                await self.__send_metrics_and_reset()
             elif self.update_pending or elapsed > 10:
                 log.debug(f"sending loaded model metrics after {int(elapsed)}s wait")
-                self.__send_metrics_and_reset()
+                await self.__send_metrics_and_reset()
 
     def _model_loaded(self, max_throughput: float) -> None:
         self.system_metrics.model_loading_time = (
@@ -130,9 +144,9 @@ class Metrics:
 
     #######################################Private#######################################
 
-    def __send_delete_requests_and_reset(self):
+    async def __send_delete_requests_and_reset(self):
 
-        def send_data(report_addr: str, success: bool) -> bool:
+        async def send_data(report_addr: str, success: bool) -> bool:
             data = {
                 "worker_id": self.id,
                 "request_idxs": [r.request_idx for r in self.model_metrics.requests_deleting if r.success == success],
@@ -141,24 +155,25 @@ class Metrics:
             full_path = report_addr.rstrip("/") + "/delete_requests/"
             for attempt in range(1, 4):
                 try:
-                    res = requests.post(full_path, json=data, timeout=1)
-                    res.raise_for_status()
+                    session = await self.http()
+                    async with session.post(full_path, json=data) as res:
+                        res.raise_for_status()
                     return True
-                except requests.Timeout:
+                except asyncio.TimeoutError:
                     log.debug(f"delete_requests timed out")
-                except Exception as e:
+                except (ClientResponseError, Exception) as e:
                     log.debug(f"delete_requests failed with error: {e}")
-                asyncio.sleep(2)
+                await asyncio.sleep(2)
                 log.debug(f"retrying delete_request, attempt: {attempt}")
 
         for report_addr in self.report_addr:
-            success = send_data(report_addr, success=True) and send_data(report_addr, success=False)
+            success = await send_data(report_addr, success=True) and await send_data(report_addr, success=False)
             if success is True:
                 self.model_metrics.requests_deleting.clear()
                 break
 
 
-    def __send_metrics_and_reset(self):
+    async def __send_metrics_and_reset(self):
 
         def compute_autoscaler_data() -> AutoScalerData:
             return AutoScalerData(
@@ -180,7 +195,7 @@ class Metrics:
                 url=self.url,
             )
 
-        def send_data(report_addr: str) -> bool:
+        async def send_data(report_addr: str) -> bool:
             data = compute_autoscaler_data()
             full_path = report_addr.rstrip("/") + "/worker_status/"
             log.debug(
@@ -195,14 +210,15 @@ class Metrics:
             )
             for attempt in range(1, 4):
                 try:
-                    res = requests.post(full_path, json=asdict(data), timeout=1)
-                    res.raise_for_status()
+                    session = await self.http()
+                    async with session.post(full_path, json=asdict(data)) as res:
+                        res.raise_for_status()
                     return True
-                except requests.Timeout:
+                except asyncio.TimeoutError:
                     log.debug(f"autoscaler status update timed out")
-                except Exception as e:
+                except (ClientResponseError, Exception)  as e:
                     log.debug(f"autoscaler status update failed with error: {e}")
-                asyncio.sleep(2)
+                await asyncio.sleep(2)
                 log.debug(f"retrying autoscaler status update, attempt: {attempt}")
             log.debug(f"failed to send update through {report_addr}")
             return False
@@ -212,7 +228,7 @@ class Metrics:
         self.system_metrics.update_disk_usage()
 
         for report_addr in self.report_addr:
-            success = send_data(report_addr)
+            success = await send_data(report_addr)
             if success is True:
                 break
         self.update_pending = False