Valheim mods use BepInEx. Get the BepInExPack Valheim from Thunderstore (thunderstore.io/c/valheim), unzip it, and upload the contents of the BepInExPack_Valheim folder into the server root, so that BepInEx/, doorstop_libs/, start_server_bepinex.sh and winhttp.dll sit next to valheim_server.x86_64. Then open a ticket or ask Kowalski to switch the start command to the BepInEx script, because the default start command launches the plain server.
Adding mods
Mod .dll files go into BepInEx/plugins/. Configs are generated in BepInEx/config/ on first start.
Server, client or both?
- Both: anything that changes gameplay or adds items/buildings (Valheim Plus, Epic Loot, building mods). Every player installs the same mod and version, usually through the r2modman or Thunderstore Mod Manager with a shared profile code.
- Server only: admin tools, backups, anti-cheat, some balancing mods that are marked server-side.
- Client only: graphics, UI, minimap tweaks.
Mismatched mod versions cause "Incompatible version" on join or silent desync. Post your profile code in your Discord and update it together.
Updates
A game update usually breaks BepInEx mods for a few days. If the server stops loading after a Valheim patch, disable mods (rename BepInEx/plugins to plugins.off) until the authors update.