Valheim crossplay server and Xbox players

To let Xbox and Game Pass players onto a Valheim dedicated server, start it with the -crossplay argument. The server then registers a session with Microsoft's PlayFab service, prints a six-digit join code in its log, and anyone on Steam, the Microsoft Store or Xbox Series X|S can join with that code. The cost is small but real: crossplay sessions route through a relay, admin and ban lists need platform-prefixed IDs, the join code changes on every restart, and any mod that players would have to install locks the console players out. This post covers how it works, how to set it up, and when leaving it off is the better choice.

The general server setup - launch arguments, ports, the save directory - is in the Valheim dedicated server guide. This post deals only with the crossplay half.

What crossplay actually changes#

Without crossplay, a Valheim dedicated server is a Steam game server. It registers with Steam's master server, appears in the Steam-backed community list, and accepts connections from Steam clients directly on its game port. Players are identified by their 17-digit SteamID64.

With -crossplay, the server switches to a different networking backend built on PlayFab, the Microsoft service the Xbox and Microsoft Store versions use for multiplayer. Three things follow from that:

• Players on any platform can join. Steam, Microsoft Store and Game Pass on PC, and Xbox Series X|S all share the same server.
• The join code becomes the main way in. Console players cannot type an IP address and port into the game, so the server publishes a short code instead.
• Identities carry a platform prefix. The server sees Steam_76561198012345678 or an Xbox user ID with its own prefix, not a bare SteamID, and every list file has to use that form.

What does not change: the world file, the world modifiers, the ten-player cap, the password requirement and the save behaviour. A world created on a Steam-only server loads on a crossplay server and back again without conversion.

Turning it on#

On your own machine, crossplay is one argument added to the normal start line:

$ ./valheim_server.x86_64 -nographics -batchmode \    -name "Longship Crew" -port 2456 -world "Midgard" \    -password "herring-barrel-42" -public 1 -crossplay

There is no value - the argument is either present or absent. Remove it and restart to go back to a Steam-only server. Nothing in the world file records which mode it was last run in.

On a panel-based host the same thing is a field on the Startup tab. RE:NODE's Valheim servers ship with crossplay already on, because most groups that ask have at least one person on Game Pass; if yours does not, switching it off is a Startup tab change and a restart.

Once the server is up, watch the log for the session line. It includes the join code:

Session "Longship Crew" with join code 483920 and IP 203.0.113.10:2456 is active with 0 player(s)

The exact wording can shift between game versions, but the code is always in it. If there is no join code at all, the server did not register with PlayFab; the troubleshooting section below covers why.

Joining from each platform#

Each platform has its own path into the same server.

On every platform the join code is entered under Join Game in the main menu, in the field for adding a server or code. After entering it, the player is asked for the server password exactly as on Steam.

Steam players on a crossplay server can still use Add Server with 203.0.113.10:2456 and connect directly. That is useful when PlayFab is slow, and it is one reason to keep the game ports open even though console players never touch them directly. Game server ports explained goes through why a server has both a game port and a query port, and what each is for.

The community list does show crossplay servers, but with thousands of entries and a weak filter it is the least reliable way in for anyone. Give your group the code.

Xbox account settings that block joining#

The most common crossplay complaint is "the Xbox player gets an error and everyone else is fine". The cause is almost always on the Xbox account, not on the server.

• Cross-network play. Xbox privacy settings have an option for whether the account can join cross-network play. If it is blocked, the player cannot join a session that includes PC players. It is under the account's privacy and online safety settings, and the exact menu path moves between dashboard updates.
• Child accounts. A child account in a Microsoft family group needs a parent to allow multiplayer and cross-network play. The parent changes this from the family settings, not from the console the child is using.
• Xbox network status. If Xbox network services are degraded, the PlayFab side of crossplay can fail while Steam players joining by IP are unaffected. That pattern - Steam fine, everyone else failing - points to the service rather than your server.
• Game Pass PC. The Microsoft Store and Game Pass versions on PC go through the same PlayFab path as the Xbox and use the Xbox app for sign-in. If the Xbox app is signed into a different account than the player expects, the game uses that one.

None of this is visible from the server log beyond the absence of a connection attempt. If an Xbox player's attempt never appears in the log at all, look at their account before you look at your server.

Admins, bans and allow lists with platform IDs#

On a Steam-only server, adminlist.txt, bannedlist.txt and permittedlist.txt contain bare SteamID64s. On a crossplay server the server identifies players by platform-prefixed IDs, and the list files must match.

// Steam player on a crossplay serverSteam_76561198012345678// Xbox or Game Pass player, as it appears in the server logXbox_2535412345678901

The safest way to get an ID right is not to type it from memory. Have each player join once, then read their ID from the server log, where each connection is recorded with the identity the server will match against. Copy it exactly, prefix and all. If a server moves between crossplay and Steam-only modes, keep both forms of a Steam admin's ID in the file so they keep their rights either way.

The files are re-read while the server runs, so adding an admin does not need a restart. A non-empty permittedlist.txt turns the server into an allow list for everyone, on every platform; that is a reasonable choice for a private group, but forgetting to add the Xbox players' IDs is a common way to lock them out without realising.

Admin powers themselves are the short vanilla list: kick, ban, unban, banned, save and a few more, typed into the in-game console opened with F5. That console is a keyboard affair on PC - it has to be enabled with the -console launch option on Steam - so in practice a PC player does the admin work even on a mostly-Xbox server. The full command table is in the dedicated server guide.

Mods and crossplay#

This is the trade-off that decides most groups.

Xbox players cannot install mods, and the Microsoft Store and Game Pass PC versions are awkward to mod at best. Valheim's mod ecosystem runs on BepInEx, and most mods that change gameplay must be installed on both server and client at the same version. So:

Mod libraries that enforce matching versions on connect will kick an unmodded Xbox player immediately. If a group with console players wants mods, the only workable approach is to keep the server-side-only column and nothing else. Valheim mods with BepInEx on a server covers which mods fall in which column and how to install them.

If your group is all on PC, this trade-off disappears, and so does most of the reason to run crossplay.

Performance and what the relay costs#

Crossplay sessions route through a relay rather than straight from the player to your server. For players in the same region as the server, that adds a small amount of latency - usually a few milliseconds, sometimes more if the relay chosen is not close to either end. For most groups this is not noticeable during normal play.

Where it matters is Valheim's zone ownership model: the player who first enters an area simulates it for everyone. An Xbox player on a relayed connection who walks into the boss arena first is now the source of every monster's movement for everyone else. If combat feels soft only when a particular player is present, that is the mechanism, and the practical fix is to have the best-connected player enter busy areas first. Valheim server lag explains zone ownership in detail.

A Steam-only group gains nothing from crossplay and loses a little: the extra backend, the prefixed IDs and the restart-dependent join code. If nobody in the group is on Xbox or Game Pass, leave it off.

Version mismatches across platforms#

A Valheim server and its clients must run exactly the same game version. On a crossplay server that means Steam, Microsoft Store and Xbox clients must all be on the version the server runs.

Iron Gate usually releases patches on all platforms at the same time, but the Xbox and Microsoft Store builds can arrive later than Steam's if certification takes longer. In the gap, either the Steam players or the Xbox players cannot connect, depending on which version the server is running. The practical rule: on patch day, check that every platform has the update before restarting the server onto it.

The other version trap is the public test branch. A server updated to a public test build accepts only players on that same test build, which console players cannot get. Keep a crossplay server on the default branch.

Before any update, take a backup. On RE:NODE, backup slots are included on every Valheim plan and a restore is one button, so an update that splits the group can be undone without a ticket - see Valheim server backups and world corruption for the full routine.

Troubleshooting#

No join code in the log. The server did not register with PlayFab. Check that -crossplay is really in the start line (on a panel, that the variable saved), then restart. If it still fails, the PlayFab service may be degraded; Steam players can still join by IP in the meantime.

Xbox player gets a generic connection error. Check their cross-network play privacy setting, then whether they are a child account, then Xbox network status. If their attempt never reaches the server log, the block is on their side.

An admin lost their rights after enabling crossplay. The admin list holds a bare SteamID. Add the Steam_ prefixed form from the server log.

The join code worked yesterday and not today. The server restarted and the code changed. Read the new one from the log or the panel console.

Steam players connect, everyone else does not. That pattern points at the PlayFab path: the service, or the Xbox accounts. Your ports are fine, or Steam players could not join by IP either.

An Xbox player is kicked immediately after connecting. A mod on the server enforces a client mod list. Remove version-checking mods, or accept that the server is PC-only.

FAQ#

Do Xbox players need anything special to join a crossplay server?

They need the current game version, the six-digit join code, the server password and an Xbox account that allows cross-network play. Nothing is installed, and no mods are possible on console.

Can I give the server a fixed join code?

No. The code is generated each time the server registers its session and changes on restart. Steam players can always use the address instead; console players need the current code.

Does crossplay make the server slower?

Not measurably for the server itself. Relayed players may see slightly higher latency, which matters most when they own a busy zone. A Steam-only group should leave crossplay off because it gains nothing.

Can an Xbox player be an admin?

Their ID can be in adminlist.txt and the server will grant the rights, but the admin console is opened with a keyboard key and is really a PC feature. In practice a PC player handles kicks and bans.

Can I move our Xbox world onto a dedicated server?

Not as easily as a Steam world. Xbox and Game Pass saves are stored in a containerised format rather than as plain .db and .fwl files. How to upload a Valheim save covers what is possible and where to check for the current method.