diff --git a/video-gen-api/app/api/v1/invoice_headers.py b/video-gen-api/app/api/v1/invoice_headers.py
index 4a294904..bd02a5bb 100644
--- a/video-gen-api/app/api/v1/invoice_headers.py
+++ b/video-gen-api/app/api/v1/invoice_headers.py
@@ -22,18 +22,18 @@ router = APIRouter(prefix="/invoice-headers", tags=["invoice-headers"])
 def _header_to_out(header) -> dict:
     return {
         "id": header.id,
-        "userId": header.user_id,
+        "user_id": header.user_id,
         "type": header.type,
         "name": header.name,
-        "taxNo": header.tax_no,
-        "registerAddress": header.register_address,
-        "registerPhone": header.register_phone,
-        "bankName": header.bank_name,
-        "bankAccount": header.bank_account,
+        "tax_no": header.tax_no,
+        "register_address": header.register_address,
+        "register_phone": header.register_phone,
+        "bank_name": header.bank_name,
+        "bank_account": header.bank_account,
         "email": header.email,
-        "isDefault": header.is_default,
-        "createdAt": header.created_at.isoformat() if header.created_at else None,
-        "updatedAt": header.updated_at.isoformat() if header.updated_at else None,
+        "is_default": header.is_default,
+        "created_at": header.created_at.isoformat() if header.created_at else None,
+        "updated_at": header.updated_at.isoformat() if header.updated_at else None,
     }