How to Host a Project Zomboid Server: Hosted or Self Hosted (Build 42, 2026)

There are two ways to host a Project Zomboid server. Host it with us and it is online about a minute after checkout, with the join password, whitelist and Workshop mods set from the panel. Or host it yourself for free by installing the dedicated server (SteamCMD app 380870) on a Windows or Linux PC with 6 GB of RAM or more for the server and forwarding UDP ports 16261 and 16262. Either way, Knox County keeps running when the original host logs off. Build 42 has been the stable default since 29 July 2026, and Build 41 is still available on the legacy41 branch. This guide covers both ways.

Which way should you host Project Zomboid?

Time in Knox County only passes while the server runs. If the host's PC goes to sleep, so does your world, which is the main reason groups move to a hosted server. Every player needs their own copy of Project Zomboid on Steam, on the same build as the server.

How much RAM does a Project Zomboid server need?

Build 42 is noticeably hungrier than Build 41 for both RAM and CPU, and every Workshop mod and custom map adds to it. Size it for your group and your mod list:

Three or four friends with no mods? Starter. A handful of quality of life mods, or a group of around 10? Standard. A 50 mod list, map mods like Raven Creek, or a public server? Pro. Our plans hold up to 8, 16 and 32 players. At home, add a modern CPU with good single core speed and around 10 GB of disk space, plus room for Workshop mods and a growing world. More in Project Zomboid server requirements and how much RAM a game server needs.

Option 1: Host a Project Zomboid server with GamezServers

1. Pick a plan from the table above. You can move up later without losing the world. New customers get 50% off the first month.
2. Split the bill if you like. Choose Split with friends at checkout to share it between 2 and 10 people, each paying their own share by card with a 1 USD fee per share. The Standard plan split four ways is about 6 USD each. Your server starts as soon as you pay your share, and friends who make an account with the email they paid with see it in their own dashboard. Checkout also offers a Mumble voice server, free for 30 days.
3. Pay and open your server. Pay by card, Apple Pay or Google Pay. It appears as Setting up, then Online about a minute later. The control panel has the address at the top, a live console where every server command works, and buttons such as Save world, Broadcast, List players, Make admin and Start rain.
4. Pick the build. New servers run Build 42. Choose the Build 41 (legacy) server type if your group wants to finish an older world or use Build 41 only mods.
5. Set who can join. In Settings, set a Join password (leave it empty for an open server), turn on Whitelist only if you want, and choose whether to Show in the public server list. With the whitelist on, create accounts with the Add whitelisted account button.
6. Join. Each player launches Project Zomboid on the same build, clicks Join, enters the IP (the part of the address before the colon) and the port (the number after it) in separate boxes, the join password and a username and password for their account on the server, then clicks Save, selects the server and clicks Join.

The username and password a player types the first time become their account on that server, so they should reuse them, or they start over as a new character. Billing is monthly with no contract, and you can cancel any time from the dashboard. See billing and cancellation and the control panel guide.

Make yourself admin

The server creates an admin account on the first start, and its username and password are in your server Settings. Log in with it, or use the Make admin button to give your own account admin rights. In the panel console, commands run without a slash:

setaccesslevel "YourUsername" admin

In game you then get the admin panel and chat commands like /teleport and /additem. The full list is in Project Zomboid admin commands.

Where the settings files are

On our servers, the settings files sit in .cache/Server, named after the Save name setting: GamezServers.ini and GamezServers_SandboxVars.lua on a new server. They work exactly like servertest.ini on a self hosted server, so the settings below apply to either. Changing Save name starts a separate world, and the old one stays on disk.

Bring your existing world

You can upload a multiplayer save made on the same build. With the server stopped, upload your Saves/Multiplayer world folder and its files from Server into the .cache folder (the Files tab or SFTP from Settings), set Save name to the same name, then start it. See how to move a Project Zomboid save to a server.

Option 2: Host a Project Zomboid server on your own PC

The dedicated server is free, separate from the game itself, and runs on Windows and Linux.

Step 1: Install SteamCMD

Download SteamCMD from Valve. On Windows, extract it to a folder like C:\steamcmd and run it once. On Linux, install the steamcmd package or the tarball, and create a normal user to run the server rather than root.

Step 2: Download the dedicated server

The server is Steam app ID 380870 and downloads anonymously. Build 42 is the default branch, so no beta flag is needed.

Windows:

steamcmd +force_install_dir "C:\pzserver" +login anonymous +app_update 380870 validate +quit

Linux:

./steamcmd.sh +force_install_dir /home/pzuser/pzserver +login anonymous +app_update 380870 validate +quit

Run the same command after every game update, because players on a newer build cannot join an older server. To keep playing a Build 41 world, add -beta legacy41 after app_update 380870. Build 41 saves do not load in Build 42.

Step 3: Set the RAM

The server is a Java program, and its memory limit is set in ProjectZomboid64.json in the install folder. Find the vmArgs list and change the -Xmx value, for example to give the server 8 GB:

"-Xmx8g"

If there is also an -Xms line, set it to the same value. Too little memory causes stutters and out of memory crashes. Too much starves the operating system, so leave a few GB free. On our servers the Java heap is sized to your plan on every start.

Step 4: First start and admin password

Start the server with StartServer64.bat on Windows or ./start-server.sh on Linux. The very first launch asks you to create a password for the built in admin account. Type it twice and the server continues starting. When the console reports that the server has started, it is ready.

This first start also creates the config files:

• Windows: C:\Users\<you>\Zomboid\Server\
• Linux: ~/Zomboid/Server/

The world itself is saved under Zomboid/Saves/Multiplayer/.

Step 5: Edit servertest.ini

servertest.ini holds the server settings. Stop the server before editing it, because the server rewrites the file when it shuts down and your changes vanish otherwise. The settings most people change:

• PublicName and PublicDescription: how the server appears in the browser.
• Public: true to list it in the public browser, false for a private server.
• Password: a join password. Leave it empty for an open server.
• MaxPlayers: the player limit. More players need more RAM.
• PVP: true or false.
• DefaultPort: 16261 by default.
• Open: when true, anyone can create an account by joining. Set it to false for a whitelist only server, then add players with adduser.
• SafehouseAllowTrepass, PlayerSafehouse and related lines: safehouse rules.
• SaveWorldEveryMinutes: how often the world autosaves.
• WorkshopItems and Mods: covered under mods below.

The name servertest is the default server name. To run a differently named world, start the server with -servername myworld and it uses myworld.ini instead.

Step 6: Sandbox settings

servertest_SandboxVars.lua in the same folder controls the gameplay: zombie population and speed, loot rarity, when water and electricity shut off, day length, respawn and more. Common changes are more zombies for a tougher run, sprinters off, and power and water lasting longer. Edit it with the server stopped. Most sandbox changes only fully apply to a new world, and zombie counts only change in newly loaded areas, so settle these before your group starts. See best Project Zomboid server settings and how to change sandbox settings on an existing world.

Step 7: Open the ports

Project Zomboid uses UDP, not TCP. Forward these to your server's local IP:

Allow Java or the server through Windows Defender Firewall or ufw too. A TCP forward on these ports looks correct in the router but does nothing. Our port forwarding guide covers the process and testing. If your router's WAN IP is different from what a "what is my IP" site shows, your provider uses CGNAT and forwarded ports never reach you. See how to tell if you are behind CGNAT.

Step 8: Let friends connect

1. Launch Project Zomboid on the same build as the server.
2. Click Join on the main menu.
3. Enter your public IP, port 16261, the server password if there is one, and a username and password for their account on the server.
4. Click Save, then select the server and click Join.

What are the catches with hosting for free?

• The PC has to stay on. The world only moves forward while the server runs, so a PC that sleeps or restarts for updates stops it for everyone.
• Java memory tuning. As Build 42 worlds and mod lists grow, -Xmx needs raising, within what the machine has free.
• Ini files reset if you edit them with the server running.
• UDP ports have to stay forwarded on your home network, and CGNAT blocks them entirely.
• Restarts for every mod update, or players get kicked with a Workshop version error.
• Your home IP is shared with everyone who joins. See is hosting a game server at home safe.

How do you add Workshop mods to a Project Zomboid server?

• On our servers: paste the Workshop IDs in the Workshop IDs setting so the server downloads them, and the Mod IDs in Mod IDs so they switch on, separated by semicolons or commas, then restart. Build 42 needs a backslash in front of every Mod ID, which we add for you. Map mods also need their map folder in the Map setting, before Muldraugh, KY, which stays last.
• At home: two lines in servertest.ini load mods, both separated by semicolons:

WorkshopItems=2875848298;3490188370
Mods=ModIdOne;ModIdTwo

WorkshopItems takes the number at the end of each mod's Workshop URL, and the server downloads it on start. Mods takes the Mod ID from the mod's Workshop page or its files, which switches it on. Copy it exactly. Map mods also need their folder name at the start of the Map= line, before the base map.

Only use mods that support Build 42 on a Build 42 server. Players download the same mods automatically when they join. Big mod lists and map mods run best on 8 GB or more. More in how to add mods to a Project Zomboid server, how to add a Workshop collection and how to add map mods.

Build 41 or Build 42?

Build 42 brought multiplayer back with server authoritative inventories and loot, and has been the default stable branch since 29 July 2026. If your group wants to finish a Build 41 world, run the legacy41 branch instead: the Build 41 (legacy) server type on ours, or -beta legacy41 at home. Build 41 saves do not load in Build 42, and a Build 41 game cannot join a Build 42 server. Players pick their branch in Steam under Project Zomboid, Properties, Game Versions and Betas. See Build 41 vs Build 42 multiplayer.

Backups, updates and upgrades

• Backups: on our servers, click Save world, then Backup before changing mods, editing the sandbox or updating. Each server keeps 3. Mod updates are the most common way a Zomboid world breaks. At home, copy the Zomboid folder.
• Updates: our servers check Steam for a new version every time they start, so a restart after a game patch keeps them matching your players. At home, run the SteamCMD command again. See how to update a Project Zomboid server and its mods.
• Sleep when empty: our servers stop after 4 days with nobody online. The world is saved and anyone with access starts it again in one click. Time only passes while the server runs, which many groups like, but turn it off in Settings to keep the world online around the clock.
• Upgrading: if the server stutters as the world grows or after adding mods, move up a plan in Settings. The price is prorated and the new RAM applies after a restart. Your world, characters and settings stay put.

Common problems

• Stuck on "Connecting" or timing out: the ports are forwarded as TCP instead of UDP, or the firewall blocks the server. See Project Zomboid can't connect to server.
• Mod errors on join: a mod in Mods= has no matching entry in WorkshopItems=, a Mod ID is misspelled, or a mod does not support Build 42.
• "Workshop item version is different than server's": a mod updated after the server started. Restart the server. Details in our Workshop error fix.
• Config changes disappear: the file was edited while the server was running. Stop it first.
• "Server version is different": the server or the player is on another build. Update the server, and check nobody is on the legacy41 branch by accident.
• Stutters and crashes as the world grows: -Xmx is too low at home, or the plan is too small on ours. See Project Zomboid server lag and rubberbanding fix.
• Bases rolled back after a crash: always stop the server with the quit command so it saves. Killing the process can lose progress.

FAQ

Is the Project Zomboid dedicated server free?

Yes. It downloads free through SteamCMD as app ID 380870 with an anonymous login, separate from the game itself.

How much does a Project Zomboid server cost?

With us, from 14.99 USD a month for 6 GB, with 50% off the first month for new customers. Split four ways, Standard is about 6 USD each.

What ports does a Project Zomboid server use?

UDP 16261 and 16262. Both have to be forwarded as UDP.

Can I bring our existing world to the server?

Yes, if it was made on the same build. Upload the world folder and its ini and sandbox files, and set Save name to match on our servers.

Can I move my Build 41 world to Build 42?

No. Build 41 saves are not compatible with Build 42, so start a fresh world or keep the old one running on the Build 41 branch.

Why did my settings reset after I edited servertest.ini?

The server was running and wrote its own copy over yours when it stopped. Stop the server, edit, then start it.

Do friends need to install the mods?

No. Workshop mods listed on the server download automatically when players join.

How many mods can I run?

As many as your plan handles. Big mod lists and map mods run best on 8 GB or more.

Can I keep the server private to my friends?

Yes. Set a join password and turn on the whitelist, and leave public listing off so it never shows in the server browser. See how to make a Project Zomboid server private.

Do my friends need to own the game?

Yes. Every player needs their own copy of Project Zomboid on Steam, on the same build as the server.

See Project Zomboid server hosting to pick a plan and get your group into Knox County.