Project Zomboid Multiplayer: How to Play With Friends

Project Zomboid multiplayer works, it is stable, and it is one of the best co-op survival experiences on PC. It is also the game where "we can't connect" is almost never a networking problem — it is a version mismatch, and that has become far more likely since Build 42 split the game across three live branches.

Read this before you troubleshoot anything

Project Zomboid currently ships three branches at once: Build 42 Stable, Build 42 Unstable, and the Build 41 Legacy line. A client on one branch cannot join a server on another. Before you touch port forwarding, firewalls or anything else, check that every player and the server are on the same branch.

Project Zomboid is PC only — Windows, Mac and Linux. There is no PlayStation, Xbox or Switch version, so there is no crossplay question to answer: everyone you play with is on a PC, and the only real decision is how you host.

The Three Ways to Play Together

1. Host from inside the game

The Host button on the main menu runs a server on your own machine while you play on it. It is the fastest way to get two people into a world.

What it costs you:

• The world only exists while you are online. Nobody plays if you are asleep, at work, or your PC is off. In a game built on long-term base-building, that is the limitation that eventually ends the run.
• Your machine runs both the game and the server. The server gets heavier as the map is explored and zombies migrate, and your framerate pays for every extra player on top of that.
• Your home connection is the server's connection. Everyone else's latency is measured to your house.

Fine for a weekend with one friend. It is not how a group of six plays for three months.

2. A dedicated server

A Project Zomboid server runs independently of anyone's PC. It stays up when you log off, it holds the world, and every player connects to the same address on the same connection. This is what a persistent group wants, and the rest of this guide assumes it.

3. Split-screen

Project Zomboid supports shared/split-screen co-op on one machine — it is listed among the game's own Steam features, alongside partial controller support. Worth knowing it exists, but it has nothing to do with online play.

Branch Matching: The Thing That Actually Breaks

This deserves its own section because it accounts for most failed connections.

Your server has a Steam Beta Branch field on the Startup tab. Leave it empty for the current stable build, or set it to the branch you want — changing it requires a reinstall, so decide before people start a base.

Auto-update is off by default, and that is deliberate

Our Project Zomboid servers ship with Steam Auto Update set to off. That is not an oversight: an unattended update can move your server onto a build your players have not received yet, or onto one your mods have not been rebuilt for, and either way nobody can join until it is sorted out.

The trade-off is that you decide when to update. When a patch lands and players start seeing a version error, turn auto-update on for one restart, or reinstall on the branch you want, then tell everyone to let Steam update their client.

To pin a client to a branch, right-click Project Zomboid in Steam → Properties → Betas. To stay on current stable, choose None.

Setting Up Your Server

1. Set a server name. The Server Name field on the Startup tab is what appears in the browser if you list it publicly.
2. Set the admin password. The Admin Password field. The admin account is called admin unless you change Admin Username. Do not leave the password empty — an admin account with no password on a public server is an open door.
3. Start the server once and let it generate its config files before you change anything else.
4. Configure the world. Sandbox settings, population, loot rarity and the rest live in the server's config files — the Project Zomboid server settings guide walks through the ones worth changing.
5. Give people the address. Players use Join → Internet and enter your server's IP and port, or find it in the server list if you have made it public.

Mods Have to Match Too

If your server runs mods, every player needs the same mods, and Steam has to have finished downloading them before they connect. A mismatch produces a connection failure rather than a helpful message.

Two habits make this painless:

• Put the collection in the server's name or MOTD, so a new player knows what to subscribe to without asking.
• Change mods at a restart, never mid-session. Installing Project Zomboid mods covers the workflow.

Common Problems

• "Connection lost" immediately on join — branch mismatch, nine times out of ten. Check the server's branch against the client's Betas setting.
• Someone joins but nobody else can — the server may have hit its player cap, or the new player is missing a mod the others already have.
• The server is not in the public list — public listing takes a few minutes to register after a restart. Connect by IP in the meantime.
• Everything is fine, then the server slows over weeks — normal for a long-running world as the map fills with explored chunks and looted containers. Restart on a schedule rather than waiting for it to get bad.
• A player's character is gone after a wipe of the map files — characters live on the server, so anything that removes the save removes them.

Common Questions

Is Project Zomboid crossplay?

There are no consoles to cross to — the game only exists on PC. It is cross-platform in the sense Steam means it: the Windows, Mac and Linux builds all play together on the same server, and Steam lists the game under "Cross-Platform Multiplayer" for exactly that reason.

Can Mac and Linux players join a Windows server?

Yes. The client platform does not matter — the branch does.

How many players can one server hold?

More than most groups need. What limits you in practice is single-core speed rather than a player number — a busy Project Zomboid world benefits far more from a fast core than from many of them, which is why our plans are built on high-clock hardware.

Do I need to port forward?

Not with a rented server — it is already reachable. Port forwarding is only a concern when you host from your own PC.

What to Read Next

• Getting started with your Project Zomboid server — first boot, start to finish
• Project Zomboid server settings and config files — sandbox options and where they live
• How to install Project Zomboid mods — and keeping clients in step
• Project Zomboid admin commands — running the server once people are on it

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