---
title: "Customize the App SDK using JSON"
slug: "s3suite94-using-customize-the-ui-in-the-app-sdk-using-json"
updated: 2026-10-27T18:42:23Z
published: 2026-10-27T18:42:23Z
canonical: "docs.onespan.com/s3suite94-using-customize-the-ui-in-the-app-sdk-using-json"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.onespan.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Customize the App SDK using JSON

## Introduction

While the Nok Nok App SDKs allow you to programmatically replace the built-in user (UI) , they also offer a non-programmatic approach to making customizations to the built-in UI. Instead of programming, you edit cross-platform JSON UI configuration files that the App SDK uses at runtime to specify strings, styles, images, and more. This page tells how to modify these files to customize the user interface of your app.

If your iOS or Android application programmatically replaces the built-in UI with its own implementation, then any UI customization using a JSON UI configuration file does not apply. However, a [web app can substitute localized strings](/dpoa/docs/s3suite94-localizing-your-replacement-ui-with-the-web-app-sdk) from a JSON UI configuration file for the default strings in its own UI implementation.

## Document Overview

This document is intended for application developers, user interface designers, and internationalization engineers with knowledge of JSON.

Instructions for the following tasks are included on this page:

- [Replacing strings](/dpoa/docs/s3suite94-replacing-strings)
- [Explaining to the user why an additional authentication method is required](/dpoa/docs/s3suite94-replacing-strings#explaining-to-the-user-why-additional-authentication-is-required)
- [Using your own images](/dpoa/docs/s3suite94-using-your-own-images)
- [Giving a title, description and icon to an authenticator](/dpoa/docs/s3suite94-giving-a-title-description-and-icon-to-an-authenticator)
- [Displaying a friendly name for an authentication policy](/dpoa/docs/s3suite94-displaying-a-friendly-name-for-an-authentication-policy)
- [Modifying a style to affect one or many different views](/dpoa/docs/s3suite94-modifying-a-style-for-different-ui-elements)
- [Replacing the strings in an Android OOB notification](/dpoa/docs/s3suite94-replacing-the-strings-in-an-oob-notification)
- [Handling Dark Mode](/dpoa/docs/s3suite94-handling-dark-mode)
- [Localizing Your Replacement UI with the Web App SDK](/dpoa/docs/s3suite94-localizing-your-replacement-ui-with-the-web-app-sdk)