How to Configure Your Core Keeper Dedicated Server

Complete Core Keeper server configuration guide — ServerConfig.json settings, startup parameters, Game ID, world modes, and seasons.

Core Keeper uses both a config file and command-line arguments. Some settings only work via command line.

Config File Location

ServerConfig.json

Setting	Type	Default	Description
`gameId`	string	(auto)	Custom Game ID (min 28 chars, no `Y`, `y`, `x`, `0`, `O`)
`world`	int	`0`	World slot index (0–29)
`worldName`	string	`""`	Display name for the server
`worldSeed`	int	`0`	World generation seed (0 = random)
`maxNumberPlayers`	int	`100`	Max players (default 8 via CLI if omitted)
`worldMode`	int	`0`	0=Normal, 1=Hard, 2=Creative, 4=Casual
`seasonOverride`	int	`0`	Override seasonal events (see below)

⚠️ Important: -port, -password, and -ip can ONLY be set via command line. Config file values are ignored for these.

Argument	Description
`-batchmode`	Run without graphics (required for dedicated)
`-logfile <file>`	Log output file
`-world <0-29>`	World slot index
`-worldname "Name"`	Server display name
`-worldseed <number>`	World generation seed (0 = random)
`-worldmode <0/1/2/4>`	0=Normal, 1=Hard, 2=Creative, 4=Casual
`-season <name>`	Season override: None, Easter, Halloween, Christmas, Valentine, Anniversary, CherryBlossom, LunarNewYear
`-gameid <id>`	Custom Game ID
`-maxplayers <count>`	Max players (default 8)
`-port <port>`	Enable Direct Connect mode (required for crossplay)
`-ip <address>`	Bind IP (default 0.0.0.0)
`-password "pass"`	Server password for Direct Connect (max 28 chars)
`-datapath <path>`	Custom save location
`-allowonlyplatform <1-4>`	1=Steam, 2=Epic, 3=Microsoft, 4=GOG

Value	Mode	Description
0	Normal	Standard difficulty
1	Hard	Increased difficulty, harsher death penalties
2	Creative	Unlimited resources, building-focused
4	Casual	Easier difficulty, more forgiving

⚠️ You cannot convert between Creative and non-Creative worlds. Switching requires generating a new world on a different slot.

CLI Value	Config Value	Season
`None`	`0`	No override (follows real calendar)
`Easter`	`1`	Easter event
`Halloween`	`2`	Halloween event
`Christmas`	`3`	Christmas event
`Valentine`	`4`	Valentine's Day
`Anniversary`	`5`	Anniversary
`CherryBlossom`	`6`	Cherry Blossom Festival
`LunarNewYear`	`7`	Lunar New Year

When -port is not set, traffic routes through Steam's relay network:

When -port IS set (e.g., -port 27015):

Port	Protocol	Purpose
27015	UDP	Primary game port
27016	UDP	Secondary game port