diff --git a/packages/smooth_app/lib/helpers/user_management_helper.dart b/packages/smooth_app/lib/helpers/user_management_helper.dart
index 3c3f44cb8f9..95828ebf0ff 100644
--- a/packages/smooth_app/lib/helpers/user_management_helper.dart
+++ b/packages/smooth_app/lib/helpers/user_management_helper.dart
@@ -1,4 +1,5 @@
 import 'package:flutter/widgets.dart';
+import 'package:openfoodfacts/openfoodfacts.dart';
 
 class UserManagementHelper {
   UserManagementHelper._();
@@ -21,7 +22,7 @@ class UserManagementHelper {
       username.isNotEmpty && _userRegex.hasMatch(username);
 
   static bool isUsernameLengthValid(final String username) =>
-      username.length <= 20;
+      username.length <= OpenFoodAPIClient.USER_NAME_MAX_LENGTH;
 
   static bool isPasswordValid(final String password) => password.length >= 6;
 }
diff --git a/packages/smooth_app/lib/pages/user_management/sign_up_page.dart b/packages/smooth_app/lib/pages/user_management/sign_up_page.dart
index b295c059bd2..2dff92dd88c 100644
--- a/packages/smooth_app/lib/pages/user_management/sign_up_page.dart
+++ b/packages/smooth_app/lib/pages/user_management/sign_up_page.dart
@@ -119,7 +119,8 @@ class _SignUpPageState extends State<SignUpPage> {
                 }
                 if (!UserManagementHelper.isUsernameLengthValid(
                     _userController.trimmedText)) {
-                  return 'Username must be less than 20 characters'; // TODO(vik4114): localization
+                  const int maxLength = OpenFoodAPIClient.USER_NAME_MAX_LENGTH;
+                  return 'Username must be less than $maxLength characters'; // TODO(vik4114): localization and translation
                 }
                 return null;
               },