diff --git a/app/api/v1/query.py b/app/api/v1/query.py
index 2d907f4..5d71686 100644
--- a/app/api/v1/query.py
+++ b/app/api/v1/query.py
@@ -14,7 +14,7 @@ from app.services.rag_service import RagService
 from app.dependencies import get_db_client, get_current_user
 import httpx
 import logging
-from datetime import datetime
+from datetime import datetime, UTC
 import uuid
 
 logger = logging.getLogger(__name__)
@@ -90,10 +90,10 @@ async def bench_query(
             request_id=request_id
         )
 
-        
+
         return QueryResponse(
             request_id=request_id,
-            timestamp=datetime.utcnow().isoformat() + "Z",
+            timestamp=datetime.now(UTC).isoformat().replace('+00:00', 'Z'),
             environment=environment,
             response=response_data
         )
@@ -178,12 +178,12 @@ async def backend_query(
             reset_session=request.reset_session
         )
 
-        
+
         return QueryResponse(
             request_id=request_id,
-            timestamp=datetime.utcnow().isoformat() + "Z",
+            timestamp=datetime.now(UTC).isoformat().replace('+00:00', 'Z'),
             environment=environment,
-            response={"answers": response_data}  
+            response={"answers": response_data}
         )
 
     except httpx.HTTPStatusError as e:
diff --git a/app/services/rag_service.py b/app/services/rag_service.py
index 8415218..0e505ad 100644
--- a/app/services/rag_service.py
+++ b/app/services/rag_service.py
@@ -10,7 +10,7 @@ import logging
 import httpx
 import uuid
 from typing import List, Dict, Optional, Any
-from datetime import datetime
+from datetime import datetime, UTC
 from app.config import settings
 from app.models.query import QuestionRequest, RagResponseBenchList
 
@@ -276,8 +276,8 @@ class RagService:
         responses = []
 
         for idx, question in enumerate(questions, start=1):
-            
-            now = datetime.utcnow().isoformat() + "Z"
+
+            now = datetime.now(UTC).isoformat().replace('+00:00', 'Z')
             body = {
                 "question": question.body,
                 "user_message_id": idx,
diff --git a/app/utils/security.py b/app/utils/security.py
index a37c1bf..a27e95d 100644
--- a/app/utils/security.py
+++ b/app/utils/security.py
@@ -1,6 +1,6 @@
 """JWT token encoding/decoding utilities."""
 
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, UTC
 from typing import Optional
 
 from jose import JWTError, jwt
@@ -22,9 +22,9 @@ def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -
     to_encode = data.copy()
 
     if expires_delta:
-        expire = datetime.utcnow() + expires_delta
+        expire = datetime.now(UTC) + expires_delta
     else:
-        expire = datetime.utcnow() + timedelta(minutes=settings.JWT_EXPIRE_MINUTES)
+        expire = datetime.now(UTC) + timedelta(minutes=settings.JWT_EXPIRE_MINUTES)
 
     to_encode.update({"exp": int(expire.timestamp())})
 
diff --git a/coverage.xml b/coverage.xml
index 5cc2ffb..ca804bb 100644
--- a/coverage.xml
+++ b/coverage.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" ?>
-<coverage version="7.13.0" timestamp="1766645017585" lines-valid="617" lines-covered="594" line-rate="0.9627" branches-covered="0" branches-valid="0" branch-rate="0" complexity="0">
+<coverage version="7.13.0" timestamp="1766645335309" lines-valid="617" lines-covered="594" line-rate="0.9627" branches-covered="0" branches-valid="0" branch-rate="0" complexity="0">
 	<!-- Generated by coverage.py: https://coverage.readthedocs.io/en/7.13.0 -->
 	<!-- Based on https://raw.githubusercontent.com/cobertura/web/master/htdocs/xml/coverage-04.dtd -->
 	<sources>
diff --git a/tests/conftest.py b/tests/conftest.py
index ca32671..854a555 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -12,7 +12,7 @@ if test_env_path.exists():
 import pytest
 from unittest.mock import AsyncMock, MagicMock
 from fastapi.testclient import TestClient
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, UTC
 
 from app.main import app
 from app.dependencies import get_db_client, get_current_user
@@ -52,8 +52,8 @@ def test_user_response(test_user):
     return UserResponse(
         user_id=test_user["user_id"],
         login=test_user["login"],
-        last_login_at=datetime.utcnow().isoformat() + "Z",
-        created_at=datetime.utcnow().isoformat() + "Z"
+        last_login_at=datetime.now(UTC).isoformat().replace('+00:00', 'Z'),
+        created_at=datetime.now(UTC).isoformat().replace('+00:00', 'Z')
     )
 
 
@@ -101,7 +101,7 @@ def test_settings():
             "psi": env_settings.model_copy(),
             "prod": env_settings.model_copy()
         },
-        updated_at=datetime.utcnow().isoformat() + "Z"
+        updated_at=datetime.now(UTC).isoformat().replace('+00:00', 'Z')
     )