# Development {#ch-development}

This chapter describes how you can modify and extend NixOS.

```{=include=} chapters
sources.chapter.md
writing-modules.chapter.md
building-parts.chapter.md
bootspec.chapter.md
what-happens-during-a-system-switch.chapter.md
writing-documentation.chapter.md
nixos-tests.chapter.md
developing-the-test-driver.chapter.md
testing-installer.chapter.md
```