diff --git a/lambda/src/routes/auth/account_attached_clients.py b/lambda/src/routes/auth/account_attached_clients.py
index 8aab5e7..c1511f0 100644
--- a/lambda/src/routes/auth/account_attached_clients.py
+++ b/lambda/src/routes/auth/account_attached_clients.py
@@ -1,6 +1,5 @@
 """AccountAttachedClients route — GET /v1/account/attached_clients"""
 
-import json
 from typing import Sequence
 
 from aws_lambda_powertools.event_handler import APIGatewayRestResolver, Response
@@ -8,6 +7,7 @@
 
 from src.services.device_manager import DeviceManager
 from src.shared.base_route import BaseRoute
+from src.shared.utils import json_dumps
 
 
 class AccountAttachedClientsRoute(BaseRoute):
@@ -54,5 +54,5 @@ def handle(self, event) -> Response:
         return Response(
             status_code=200,
             content_type="application/json",
-            body=json.dumps(clients),
+            body=json_dumps(clients),
         )
diff --git a/lambda/src/routes/auth/account_device.py b/lambda/src/routes/auth/account_device.py
index a2fd0dd..489a3a3 100644
--- a/lambda/src/routes/auth/account_device.py
+++ b/lambda/src/routes/auth/account_device.py
@@ -8,6 +8,7 @@
 
 from src.services.device_manager import DeviceManager
 from src.shared.base_route import BaseRoute
+from src.shared.utils import json_dumps
 
 
 class AccountDeviceRoute(BaseRoute):
@@ -35,5 +36,5 @@ def handle(self, event) -> Response:
         return Response(
             status_code=200,
             content_type="application/json",
-            body=json.dumps(device),
+            body=json_dumps(device),
         )
diff --git a/lambda/src/routes/auth/account_devices.py b/lambda/src/routes/auth/account_devices.py
index 3cc797f..ac0b009 100644
--- a/lambda/src/routes/auth/account_devices.py
+++ b/lambda/src/routes/auth/account_devices.py
@@ -1,6 +1,5 @@
 """AccountDevices route — GET /v1/account/devices"""
 
-import json
 from typing import Sequence
 
 from aws_lambda_powertools.event_handler import APIGatewayRestResolver, Response
@@ -8,6 +7,7 @@
 
 from src.services.device_manager import DeviceManager
 from src.shared.base_route import BaseRoute
+from src.shared.utils import json_dumps
 
 
 class AccountDevicesRoute(BaseRoute):
@@ -41,5 +41,5 @@ def handle(self, event) -> Response:
         return Response(
             status_code=200,
             content_type="application/json",
-            body=json.dumps(devices),
+            body=json_dumps(devices),
         )