Configuration

All server settings are environment variables in .env. The entrypoint turns them into Valheim command line flags on every container start.

Apply changes

nano .env
./valheim update

update recreates the container, which re-reads .env.

Variable reference

Server identity

Variable	Default	Description
SERVER_NAME	Saberguard Valheim	Name shown in the server browser
WORLD_NAME	Midgard	World to load or create under config/worlds_local/. Letters, digits, - and _ only
SERVER_PASS	required	Join password. 5+ characters and it must not appear inside SERVER_NAME. Empty is allowed only with SERVER_PUBLIC=false
SERVER_PUBLIC	true	true lists the server in the community browser, false is direct-connect only
CROSSPLAY	false	true enables PlayFab crossplay for Xbox and Microsoft Store players. Also open 2458/udp in docker-compose.yaml
TZ	America/New_York	Time zone for log timestamps

Network

Variable	Default	Description
SERVER_PORT	2456	Game port (UDP)
QUERY_PORT	2457	Steam query port (UDP). Valheim always uses game port + 1, keep them in sync

Image and runtime

Variable	Default	Description
IMAGE_REPOSITORY	ghcr.io/mrguato/valheim-game-server	Image source. Change it to run a fork or a locally built image
IMAGE_TAG	latest	Image tag. Pin a release such as 2.1.0 for production
CONTAINER_NAME	valheim	Docker container name
PUID	1000	UID the server runs as. Match the owner of ./config and ./data. 0 runs as root
PGID	1000	GID the server runs as
UPDATE_ON_START	true	Run SteamCMD app_update validate on every container start
STOP_TIMEOUT	120	Seconds to wait for the world save on shutdown before the process is killed
BEPINEX	false	Load the BepInEx mod loader (BepInExPack_Valheim, baked into the image). Put plugin DLLs in config/bepinex/plugins/; their configs land in config/bepinex/config/

Game settings

All optional. Empty means Valheim’s own default.

Variable	Valheim flag	Description
SAVE_INTERVAL	-saveinterval	Seconds between world saves (default 1800)
WORLD_BACKUPS	-backups	Number of automatic world backups Valheim keeps next to the world (default 4)
BACKUP_SHORT	-backupshort	Seconds between the first automatic backups (default 7200)
BACKUP_LONG	-backuplong	Seconds between later automatic backups (default 43200)
SERVER_PRESET	-preset	normal, casual, easy, hard, hardcore, immersive or hammer
SERVER_MODIFIERS	-modifier	Space separated key:value pairs, see below
SERVER_SETKEYS	-setkey	Space separated keys, see below
SERVER_ARGS	verbatim	Anything else appended to the command line

Modifier keys and values:

Key	Values
combat	veryeasy, easy, hard, veryhard
deathpenalty	casual, veryeasy, easy, hard, hardcore
resources	muchless, less, more, muchmore, most
raids	none, muchless, less, more, muchmore
portals	casual, hard, veryhard

Set keys: nobuildcost, playerevents, passivemobs, nomap.

Example for a relaxed server:

SERVER_MODIFIERS=deathpenalty:casual raids:less
SERVER_SETKEYS=passivemobs

Presets and modifiers are applied when the world is created and whenever the server starts, the same way the in-game world modifier menu works.

Player lists

Valheim reads three files from config/, one ID per line (Steam64 IDs, or platform IDs for crossplay players):

File	Purpose
adminlist.txt	Players who can use admin console commands
bannedlist.txt	Banned players
permittedlist.txt	Whitelist. If non-empty, only these players can join

Edit them while the server runs; Valheim reloads them, but a restart is the safe way to be sure.

Volumes

Host path	Container path	Contents
./config	/config	worlds_local/ (worlds), player lists, prefs
./data	/opt/valheim	Game files from SteamCMD, reproducible
./backups	/config/backups	Backup tarballs from ./valheim backup

./config and ./data must be owned by PUID:PGID. The container fixes that on its first start when it runs as root (the default), so you normally never touch it.

Pinning an image version

IMAGE_TAG=2.1.0

Then ./valheim update only pulls that version. Tags are listed on the container image page. Watchtower only follows the tag you pinned.