From a game night for four to a public server for two hundred: how to host Project Zomboid in Build 42, what the settings mean, and the mistakes that cost people their save. Updated for Build 42.21, October 2026.
Click Host in the main menu. Easy, free, and the world only exists while you are playing. Good for friends.
Runs on its own, 24 hours a day, on your PC, a spare machine or a rented host. Needed for anything public or always-on.
Build 42 servers can hold up to 254 players since hotfix 42.20.3, and admins can still join when the server is full.
Your PC has to run the game and the server at once. Give it memory, and expect the host to have the smoothest ride.
steamcmd +login anonymous +force_install_dir /opt/pz +app_update 380870 validate +quit./start-server.sh -servername "servertest" on Linux, or StartServer64.bat on Windows. The first run creates the settings files and asks for an admin password.Zomboid/Server/ as servertest.ini (or your server's name) plus a sandbox file.Zomboid/Saves/Multiplayer/; the settings are in Zomboid/Server/. Build 42 saves cannot be downgraded.A dedicated server is controlled by a handful of files. Learn what each one does before you change anything.
Zomboid/Server/<preset>.ini: server name, ports, password, Open or whitelist, PVP, safety, safehouse rules, Discord, RCON, backups and mods.
<preset>_SandboxVars.lua: zombie settings, loot multipliers, power and water shut-offs, erosion, corpse cleanup, XP and world rules.
<preset>_spawnpoints.lua: concrete spawn locations. Custom map mods may need extra points.
<preset>_spawnregions.lua: the named regions shown to players when they join.
The default preset is usually called servertest. On Windows the folder is often C:\Users\<name>\Zomboid\Server\.
In co-op, Host > Manage Settings writes the same INI and SandboxVars pair.
Build 42 saves are not compatible with Build 41. Run each as a separate world with its own config.
These keys live in SandboxVars. The sample values below are the Apocalypse defaults on Build 42.19 unless noted.
1 = Insane, 2 = Very High, 3 = High, 4 = Normal, 5 = Low, 6 = None. Apocalypse uses 4.
Global density. Insane 2.5, Very High 1.6, High 1.2, Normal 0.65, Low 0.15, None 0.0. Custom decimals are allowed.
How much denser the world gets by the peak day. Default 1.5.
The day the peak density is reached. Default 28.
Hours between respawn checks. 0 turns timed respawn off, although migration can still move zombies around.
How long an area must go unseen before it may respawn. Default 0.
How often zombies are redistributed. Example value 12.
How far zombies follow a sound. Example value 100.
How large idle zombie clusters get outdoors. Example value 20.
A separate table for speed, strength, toughness, transmission, sight and hearing. Use the in-game menus to set it.
Older tables that list Normal as 1.0x and Insane as 4.0x do not match Build 42.19. Trust the values above.
Loot is set per category. The sample values are Apocalypse defaults; each category is a multiplier on how often those items appear.
0.8. General food.
0.6.
0.6. Melee and general weapons.
1.2. The one category above 1.
0.6.
0.6.
0.6 each.
0.6 each.
0.4.
Insane through Abundant loot factors range from 0.05 to 3.0 and set the overall rarity tier.
0 turns periodic container respawn off. A higher number sets the wait before looted containers can refill.
Stops respawn in recently visited areas when above 0.
Default 5. Containers holding at least this many items do not respawn.
Default true. Player construction and barricades block respawn.
Set in the INI. When true, claimed safehouses get no loot respawn.
Apocalypse value is 216, which is nine in-game days. Not "never".
Control how ground clutter is cleaned up.
Decide your PvP policy before anyone creates a character, and publish it. These settings are in the INI.
Set PVP=false. Players cannot damage each other.
PVP=true, SafetySystem=true, ShowSafety=true, SafetyToggleTimer=2, SafetyCooldownTimer=3. Players switch their own safety on and off with a short delay.
PVP=true with SafetySystem=false. Player damage is always on.
Admins can place these from the Admin Panel, even when global PvP is on.
Lets players claim safehouses.
When on, only admins can claim.
Whether non-members can enter. (The engine spells it "Trepass".)
Whether non-members can take items.
Whether fire can damage a safehouse.
Whether members can respawn there after death.
Minimum days a player must survive before claiming. Example 1.
Real-world hours of inactivity before a member is removed. Example 144.
While the owner is online, the house acts like a normal house.
Whether non-residential buildings can be claimed.
When true, all fire is disabled except campfires, including Molotovs.
Faction, FactionDaySurvivedToCreate and FactionPlayersRequiredForTag. These are independent of safehouse claims.
Open=true lets players join without a pre-made account. false requires whitelisted accounts.
Creates an account.
Removes a user from the whitelist.
Sets Admin, Moderator, Overseer, GM or Observer. Example: /setaccesslevel "rj" "moderator".
Promotes to admin. Prefer /setaccesslevel when you want a specific level.
Open it from the admin icon on the HUD control strip. It manages users, tickets, non-PvP zones, item lists and some sandbox options.
RCONPort and RCONPassword only if you need remote console access, and use a strong password.Turns on the global text chat link.
Your bot token. Treat it as a secret.
Name of the chat channel.
Name of the log channel.
Name of the commands channel.
Create the bot and channels in Discord first, then set the keys, restart, and confirm messages appear in the server log.
WorkshopItems= is a semicolon-separated list of Workshop IDs. It downloads the content. Example: WorkshopItems=1234567890;0987654321Mods= is a semicolon-separated list of mod IDs. It turns the mod folders on. Example: Mods=ModIdOne;ModIdTwoZomboid folder.Never edit live configuration files while the world is saving. Keep an offline copy of the full folder before any major change. The backup keys in the INI are BackupsCount, BackupsOnStart, BackupsPeriod and SaveWorldEveryMinutes.
ZombieSpeedFiles=Sprinters in servertest.ini, or through Sandbox Options > Zombie Lore > Speed for a new game. Existing worlds can switch, but only newly generated chunks get the new population.VehicleEasyUse=false and FuelStationGas=Scarce.app_update 380870 -beta unstable validate in SteamCMD for the Unstable branch.You do not need to own the game to host. Install SteamCMD, then:
steamcmd +force_install_dir /opt/pzserver +login anonymous +app_update 380870 validate +quitjre64/) and start-server.sh../start-server.sh -adminpassword 'ChooseSomethingLong'. This creates the admin account and generates the config files.SERVER STARTED in the console.quit at the console. Killing the process can corrupt the world.ufw allow 16261/udp and ufw allow 16262/udp. Forgetting 16262 makes players time out on the loading screen. Behind CGNAT, port forwarding will not work.Selects the config and save profile. Default is servertest.
Root for configs, saves and logs. Default is ~/Zomboid.
Sets the admin password on first boot.
Java heap limit, for example -Xmx7g on a 10 GB machine.
~/Zomboid/Server/servertest.ini~/Zomboid/Server/servertest_SandboxVars.lua~/Zomboid/Saves/Multiplayer/servertest/4 to 5 GB heap on a 6 to 8 GB machine. Runs, but with little headroom.
6 GB heap on 10 GB. The practical entry point.
8 to 9 GB heap on 12 GB. Where most settled groups belong.
11 to 12 GB heap on 16 GB.
/save before any restart or backup. A clean quit saves too; kill -9 does not.PublicName, Public, Password, MaxPlayers, PVP, PauseEmpty, Open, Mods, WorkshopItems. Mod lists use semicolons, not commas./setaccesslevel <user> admin from the console.Up to 254 since hotfix 42.20.3. Hardware, not the game, is the real limit.
16261 and 16262, UDP, on your router or host firewall.
No. Everyone must be on the same build and branch. Run a separate legacy41 server for Build 41.