> For the complete documentation index, see [llms.txt](https://spiderheck-modding.gitbook.io/guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://spiderheck-modding.gitbook.io/guide/making-mods/patching.md).

# Patching

To modify the game code, BepInHecks uses a library called [Harmony](https://harmony.pardeike.net/articles/intro.html). This allows you to modify the code in memory, without editing any files on disk.

An example usage of Harmony is included in the example mod from earlier, where it patches the `VersionNumberTextMesh.Start` method.

The official Harmony documentation can be found [here](https://harmony.pardeike.net/articles/intro.html). However, BepInHecks uses a slightly modified version called HarmonyX. It provides some extra features useful for modding, and a list of differences between it and the original Harmony can be found [here](https://github.com/BepInEx/HarmonyX/wiki/Difference-between-Harmony-and-HarmonyX).