---
title: Mod settings and existing UI APIs
summary: When to use a settings library and when to build a custom window.
section: ui
kind: guide
status: reference
tags: ["X4","modding","ui","settings"]
sources: ["https://github.com/bvbohnen/x4-projects/tree/master/extensions/sn_mod_support_apis"]
---
## A setting does not always need a window


A toggle, number or mode selector can use a shared extension settings interface. A special panel can use a [custom window](wiki:create-ui). One third-party option is X4 Mod Support APIs, `sn_mod_support_apis`: Simple Menu API supports settings/menu construction, and Lua Loader API assists loading and delayed initialization.



## Distinguish the library from the game


`Register_OnLoad_Init` and MD `Simple_Menu_Options` belong to that library; they are not guaranteed in clean X4. Read the installed version's documentation, declare `content.xml` and `ui.xml` dependencies, and wait for readiness.



## A setting's route


Define a unique ID, text, type and default; register a change handler; validate and store the value in the appropriate context. Defaults must not overwrite saved choices on every load. Menu rebuilding must not repeat an expensive operation.



## Verification


Test first opening, changing the value, reopening, saving and loading. Check missing or incompatible dependencies separately. Use current library documentation rather than an unverified example for an older release.