Valheim BepInEx: Install BepInExPack and Mods on a Server

BepInEx is the mod loader behind practically every Valheim mod. For Valheim you do not use the generic BepInEx release from GitHub, but BepInExPack Valheim from Thunderstore: a version preconfigured for Valheim and maintained by the Valheim modding community. This guide shows how to install it on a Linux or Windows dedicated server, where mods and configs go, which mods belong on the server or on the players' PCs, and what changed with Valheim 1.0 (9 September 2026).

Before you start: Valheim 1.0 and mods

No official mod support. Iron Gate does not support mods, so you use them at your own risk and a game update can break them. There is no Steam Workshop and no mod support on consoles.
1.0 broke older mods. According to the Valheim Modding Wiki, the 1.0 update contained breaking changes, so many older mods need an update. Check each mod's last update date and changelog, and be careful with mods marked Deprecated on Thunderstore.
Use the latest pack. At the time of writing that is BepInExPack Valheim 5.4.2351 (24 September 2026), based on BepInEx 5.4.23.5.
Back up first. Stop the server and save your world files (.db and .fwl) before you add or update mods.

What is inside BepInExPack Valheim

Download the pack with the Manual Download button on its Thunderstore page and extract it on your own PC. Inside the BepInExPack_Valheim folder you will find:

BepInEx/ with core (the loader itself) and config/BepInEx.cfg
winhttp.dll and doorstop_config.ini: the loader hook for Windows
doorstop_libs/: the loader hook for Linux (and macOS)
start_server_bepinex.sh and start_game_bepinex.sh: start scripts for Linux

There are no plugins or patchers folders yet. BepInEx creates them itself, together with BepInEx/LogOutput.log, the first time the server starts with the loader active.

Install on a Linux dedicated server

Stop the server and make a backup.
Upload the contents of BepInExPack_Valheim (not the folder itself) to the server folder that contains valheim_server.x86_64, for example via SFTP.
Make the script executable: chmod u+x start_server_bepinex.sh.
Open start_server_bepinex.sh and adjust the last line with your own -name, -port, -world and -password, just like in Valheim's own start script. The password needs at least 5 characters and may not appear in the server name.
Start the server with ./start_server_bepinex.sh. If it works, you see BepInEx messages in the terminal and BepInEx/LogOutput.log appears.

Install on a Windows dedicated server

Stop the server and make a backup.
Copy the contents of BepInExPack_Valheim into the dedicated server folder, next to valheim_server.exe. With Steam that is normally C:\Program Files (x86)\Steam\steamapps\common\Valheim dedicated server. The BepInEx folder, winhttp.dll and doorstop_config.ini must sit at that top level.
Start the server as usual with start_headless_server.bat. The winhttp.dll loads BepInEx automatically.

Starting the server from r2modman or Thunderstore Mod Manager? Then edit start_headless_server.bat and add %* at the end of the line that launches the server, otherwise the mod manager's parameters are dropped. Also use a separate profile for the server and for playing, so the two do not lock each other's files.

On a game panel or hosted server

Most hosting panels start valheim_server.x86_64 directly. The BepInEx files are then present, but the loader never starts, because on Linux it needs the environment variables that start_server_bepinex.sh sets:

export DOORSTOP_ENABLED=1
export DOORSTOP_TARGET_ASSEMBLY=./BepInEx/core/BepInEx.Preloader.dll
export LD_LIBRARY_PATH="./doorstop_libs:$LD_LIBRARY_PATH"
export LD_PRELOAD="libdoorstop_x64.so:$LD_PRELOAD"

The startup command has to include these lines or run the script. On a HostValues Valheim server this is a switch: upload the files via SFTP or the file manager, set BepInEx mods to 1 in the Startup tab of the game panel and restart. The panel then sets these variables for you. Keep Crossplay at 0 on a modded server, because with crossplay on, BepInEx mods are not supported. No LogOutput.log after a restart means the loader is still not active.

Where mods and configs go

Mods: the mod's .dll goes into BepInEx/plugins/. If a mod comes with its own folder (for example with asset or translation files), upload that whole folder into plugins.
Dependencies: install everything listed under Dependencies on the mod's Thunderstore page, such as the Jötunn library. BepInExPack itself is already there.
Configs: after the first start with a mod, its config file appears in BepInEx/config/, usually named after the mod's GUID. Stop the server, edit, start again. Many mods sync their server config to all players, so the server file is the one that counts.
Patchers: BepInEx/patchers/ is only for the rare mods that explicitly ask for it.

Check BepInEx/LogOutput.log after every change. Each loaded mod gets a line like Loading [ModName 1.0.0], and since pack 5.4.2351 the line Chainloader startup complete ends with how many mods loaded, were skipped or failed.

Server-side, client-side or both

Type	Install on	Typical mods
Server-side only	The server	Discord chat bridges, scheduled restarts, admin commands, world or event tweaks. Players need nothing.
Both	Server and every player, same version	New items, recipes, creatures and building pieces, and mods that sync configs or check versions. A mismatch blocks the connection.
Client-only	Only the player who wants it	HUD and UI changes, minimaps, camera tweaks. Not needed on the server.

Thunderstore has Server-side and Client-side categories, but the mod description is always leading. When in doubt, install a mod on both sides.

Players: use a mod manager

For players, a mod manager is by far the easiest route. BepInExPack's own instructions recommend Gale, Thunderstore Mod Manager or r2modman: click Install with Mod Manager on the Thunderstore page and always start Valheim through the manager.

Share one mod list: in r2modman, go to Settings, Profile, Export profile as code. Players import it via Import / Update, Import new profile, From code, and get the same mods, versions and configs.
Fill the server from your profile: Settings, Browse profile folder opens the profile. Upload the server-relevant mods from its BepInEx/plugins and BepInEx/config folders, and leave client-only mods out.
Not every mod is on Thunderstore anymore: the Valheim Modding Wiki notes that updates of some popular authors (such as Azumatt, Smoothbrain and OdinPlus) are published on Hexium. Gale can install from both Thunderstore and Hexium.

Crossplay and mods

Console players on Xbox, PlayStation 5 and Switch 2 cannot install mods, and with crossplay on, BepInEx mods are not supported. Mods and crossplay therefore do not mix: a modded server is for PC players only. Keep crossplay off on a modded server; in the HostValues panel that is the Crossplay option under Startup, which is 0 (off) by default. Without crossplay the server works as a classic Steam server that players join via the server browser or IP:port with the password.

Troubleshooting

No LogOutput.log: BepInEx is not loading. Check that the files sit at the top level next to the server executable and that the server starts through the BepInEx launcher.
Server crashes on start after an update: update BepInExPack first, then libraries such as Jötunn, then the mods. Remove mods that were not updated for 1.0 one by one until the server starts.
Players cannot connect: usually a mod or version mismatch. Compare the players' LogOutput.log with the server's to spot the difference.

No server running yet? Start with our Valheim server setup guide.

Frequently asked questions

Which BepInEx do I need for Valheim 1.0?

BepInExPack Valheim by denikson on Thunderstore, currently version 5.4.2351 (based on BepInEx 5.4.23.5). Do not use the generic BepInEx release from GitHub: it is not configured for Valheim.

Where do I put Valheim mods on a dedicated server?

Mod files go into BepInEx/plugins/ on the server, and their config files appear in BepInEx/config/ after the first start. Only upload server-side mods and mods that are needed on both sides; client-only mods stay on the players' PCs.

Do players need BepInEx to join a modded server?

Only if the server runs mods that must also be installed on the client. For purely server-side mods, players can join with an unmodded game. As soon as a mod is needed on both sides, every player needs BepInEx and the same mod versions.

Can console players join a modded Valheim server?

No. Console players cannot use mods, and with crossplay on, BepInEx mods are not supported. A modded server keeps Crossplay at 0 and is for PC players only.

Why are my mods not loading on the server?

If BepInEx/LogOutput.log does not appear, BepInEx is not starting: on Linux the server has to start through start_server_bepinex.sh or with the same environment variables. If the log does exist, look for errors and for mods that were not updated for Valheim 1.0.