diff --git a/api/views.py b/api/views.py
index 794255e..1eea33a 100644
--- a/api/views.py
+++ b/api/views.py
@@ -251,7 +251,27 @@ class MockUploadView(APIView):
     permission_classes = [AllowAny]
 
     def put(self, request):
-        return Response({"status": "success", "message": "Mock upload successful"})
+        s3_key = request.query_params.get('key')
+        if not s3_key:
+            return Response({"error": "key query param is required"}, status=status.HTTP_400_BAD_REQUEST)
+        
+        # Define local mount directory (falls back to local project relative path if not on EC2)
+        base_dir = os.environ.get('UPLOAD_MOUNT_DIR', '/home/ubuntu/mnt/s3files/supplierdocuments')
+        if not os.path.exists('/home/ubuntu/mnt/s3files/supplierdocuments') and not os.environ.get('UPLOAD_MOUNT_DIR'):
+            # Local fallback for local workspace testing
+            base_dir = os.path.join(settings.BASE_DIR, 'mnt/s3files/supplierdocuments')
+
+        file_path = os.path.join(base_dir, s3_key)
+        
+        try:
+            # Ensure target directories exist
+            os.makedirs(os.path.dirname(file_path), exist_ok=True)
+            # Save raw request body to disk
+            with open(file_path, 'wb') as f:
+                f.write(request.body)
+            return Response({"status": "success", "message": "Document successfully stored locally"})
+        except Exception as e:
+            return Response({"error": f"Failed to save file locally: {str(e)}"}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)
 
 class PresignedUrlView(APIView):
     permission_classes = [IsAuthenticated]
@@ -303,9 +323,9 @@ class PresignedUrlView(APIView):
                 )
             except Exception as e:
                 print("S3 presigned URL generation failed, falling back to local mock upload endpoint:", e)
-                presigned_url = request.build_absolute_uri('/api/profile/mock-upload/')
+                presigned_url = request.build_absolute_uri(f'/api/profile/mock-upload/?key={s3_key}')
         else:
-            presigned_url = request.build_absolute_uri('/api/profile/mock-upload/')
+            presigned_url = request.build_absolute_uri(f'/api/profile/mock-upload/?key={s3_key}')
 
         return Response({
             'presigned_url': presigned_url,