XLib is a Vintage Story mod by Xandu. XLib is a library for Vintage Story mods that adds an interface for skills, abilities, effects, synchronization, and saved data.
Why this mod is worth installing
This dependency is useful for mod authors who want to build custom progression or ability systems without creating all the supporting infrastructure themselves. Regular players generally need it only when another installed mod lists XLib as a requirement.
What XLib adds
XLib is a backend library rather than a standalone gameplay expansion. It exposes tools that other mods can use to register skills, abilities, and temporary or persistent effects in Vintage Story.
The library also handles communication between the server and connected clients, helping custom systems keep their state consistent in multiplayer. It includes data saving and loading so supported progression can survive a world restart.
For player-facing use, XLib can provide a dialog opened with the O key by default. Its main value, however, is giving mod developers a reusable foundation for their own skill and ability designs.
Where to download XLib
The official Vintage Story Mod DB page is the right place to get the current release through the in-game mod manager.