How to Host a Project Zomboid Dedicated Server

Three ways to play Project Zomboid together

• Host from the game. The Host button on the main menu starts a server on your PC with you in it. It is the quickest way to play an evening with friends, but the world only exists while you are in the game.
• Run the dedicated server on your PC. The Project Zomboid Dedicated Server is a free Steam tool. It runs without the game open, so friends can play while you are away from it — as long as the PC stays on and the ports are forwarded on your router.
• Rent a server. The same dedicated server, on a machine in a data centre. Nobody has to leave a PC running, and nobody has to touch the router.

If you only play when everybody is online at the same time, hosting from the game is enough. The moment someone wants to log in on their own — to farm, to finish a base, to loot while the others sleep — you need a dedicated server.

What a Project Zomboid server needs

RAM

Memory is the resource that runs out first. An empty Build 42 server uses about 3 GB, then roughly half a gigabyte more per active player, plus whatever your Workshop mods need. Players spread out across the map cost more than players in one base, because every area someone stands in is loaded and simulated. Build 41 is lighter: an empty B41 server sits around 2 GB.

Ports

The server listens on two UDP ports: 16261 and 16262. Both are needed, and both are UDP — opening TCP ports does nothing. (Very old guides list 8766 and 8767; those were only used before version 41.77.)

The software

The server is a separate, free Steam app: Project Zomboid Dedicated Server, Steam app 380870. It runs on Windows, Linux and macOS. Its settings live in two files, both in Zomboid/Server/:

• servertest.ini — the server itself: name, password, player limit, PvP, mods.
• servertest_SandboxVars.lua — the world rules: zombie population, loot, XP, day length.

The world is saved in Zomboid/Saves/Multiplayer/servertest. "servertest" is just the default server name; every file follows it.

Host a dedicated server on your own PC

On Windows

1. Install the server. In Steam, open the Library, switch the filter to Tools and install Project Zomboid Dedicated Server. Do not start it from Steam — it is started from a script.
2. Set the memory. In the install folder, open StartServer64.bat in a text editor and find -Xmx. The file ships with a 16 GB value; set it to what your PC can spare, for example -Xmx6g, and leave enough for Windows and, if you also play on that PC, for the game.
3. First start. Run StartServer64.bat. On the first start the server asks you to choose a password for the admin account it creates. Write it down. When the console prints that the server has started, it is running.
4. Stop it and edit the settings. Type quit in the console. Open %USERPROFILE%\Zomboid\Server\servertest.ini and set at least PublicName, Password (if the server is private) and MaxPlayers. Start the server again.
5. Open the ports. Allow the server through Windows Firewall, then forward UDP 16261 and 16262 on your router to the PC's local IP address.
6. Invite your friends. They join with your public IP address and port 16261. You join from the same PC with 127.0.0.1.

On Linux

Install it with SteamCMD as an ordinary user — the server should not run as root:

steamcmd +force_install_dir ~/pzserver +login anonymous +app_update 380870 validate +quit
cd ~/pzserver
bash start-server.sh

For Build 41, add -beta legacy41 after app_update 380870. On Linux the memory setting lives in ProjectZomboid64.json rather than a .bat file. Run the server inside tmux or screen so it keeps going after you close the terminal, and stop it with quit so the world is saved.

Host it on HytHost instead

A rented server skips the install, the memory setting and the router. The steps are:

1. Order and pick the build. On Project Zomboid hosting, pick a plan — or a Custom server from 6 to 32 GB — and choose Build 42 or Build 41 at checkout. The server is created automatically after payment.
2. Open the Startup tab. In your GamePanel, the Startup tab holds the settings you will change most: server name, server password, max players, public listing, PvP, Workshop items and mod IDs. The server writes these into servertest.ini every time it starts, so set them here rather than in the file.
3. Set the admin password. Fill in the admin password in the Startup tab before the first start. If you leave it empty, one is generated for you and saved in admin-password.txt in your files. It is used when the admin account is created on the first start.
4. Join by IP. In Project Zomboid choose Join, add the server with the IP address and port shown in your panel, and the server password if you set one. On a shared IP your panel shows the ports assigned to you; the Dedicated IP add-on gives the server its own address on the default ports 16261 and 16262.
5. Log in as admin once. Join with the username admin and the admin password, and promote your own account (see making yourself admin below). After that you can play on your normal account.

Everything else — the sandbox file, the world folder, backups and the live console — is in the same panel. Automatic backups are included, and if you already have a world on your PC or with another host, the migration is free.

Build 42 or Build 41: which one to run

Build 42 is the current game. It became the stable branch with version 42.20 on 29 July 2026, multiplayer included, and brings the new crafting, basements, animals and lighting. A new group with no strong attachment to old mods should start here.

Build 41 (41.78) is the previous branch. It stays available because a lot of Workshop content — big map packs, vehicle packs, overhaul mods — was built for it and has not been updated, and some groups prefer its balance.

• Saves do not cross. A Build 41 world does not open on Build 42. Switching builds means starting a fresh world.
• Mods are per build. Many mods ship separate versions for 41 and 42, and some exist for only one. Check every mod on your list before you choose.
• Everyone has to match. Players on Build 42 cannot join a Build 41 server, and the other way round. To play Build 41, each player selects it in the game's Betas tab in Steam.

On HytHost you can change the build later from the Startup tab and reinstall. Because the saves are incompatible, the switch starts a fresh world; the old one is moved to a folder of its own on the server, not deleted.

Making yourself admin and adding mods

Admin

The server creates one admin account, admin, on its first start. Log in with it once, then give your everyday account admin rights from the chat:

/setaccesslevel "YourName" admin

Disconnect and join again so the change takes effect, and the admin tools appear on your own account. The same command takes moderator or gm for helpers with fewer powers. The full list — teleport, items, whitelist, bans, saving — is in our Project Zomboid admin commands guide.

Workshop mods

A mod needs two entries in servertest.ini:

• WorkshopItems — the number at the end of the mod's Steam Workshop URL. The server downloads it.
• Mods — the mod ID, which is the id= line of the mod's mod.info, often not the same as its name. On Build 42 every ID needs a backslash in front, for example \ModA;\ModB.

Separate several entries with semicolons, restart, and players download the mods automatically when they join. On HytHost both fields are in the Startup tab. Map mods, load order and checking for mod updates are covered in Project Zomboid server and sandbox settings.

Server not showing up, or friends cannot connect

Almost every case is one of these, roughly in order of how often they happen:

1. It is not meant to be listed. Public=false is the default, so the server does not appear in the in-game browser. That is fine — join it by IP and port. Set it to true only if you want strangers to find it.
2. The ports are closed. At home, both UDP ports have to be forwarded and allowed through the firewall. Forwarding only 16261, or forwarding TCP, is the classic mistake.
3. Different builds or versions. A Build 42 player cannot join a Build 41 server. After a game update, the server and every player need the same version, so update the server too.
4. Mods do not match. If a mod failed to download on the server, or a player's copy differs, the connection drops. Read the server console: it names the mod.
5. Testing from the same network. Joining your own home server through its public IP fails on many routers. From the PC itself use 127.0.0.1; friends on the same Wi-Fi use the PC's local IP.
6. Wrong password or account. The server password is not the same thing as your account password on that server. With a whitelist, only accounts an admin has added can join.

What a Project Zomboid server costs

At home the server is free. You pay in electricity for a PC that stays on, in the RAM the server takes from your own games, and in the evenings when the PC was off and nobody could play. For a group that plays together at fixed times, that is a good deal.

Rented, you pay for the memory the server needs. On HytHost every plan costs the same per gigabyte, and a Custom server of any size from 6 to 32 GB costs exactly what a fixed plan of that size would:

For most friend groups with mods, Muldraugh, 8 GB, is the sensible start. Every plan includes automatic backups, Workshop mods, both builds, scheduled restarts, DDoS filtering and a 99.9% Uptime SLA, and upgrades keep your world in place.