Valheim crossplay on a dedicated server

Crossplay is not a consequence-free tick box on Valheim. It moves the server onto a different network from Steam's, and that shows up in places other than the player list.

What crossplay turns on

The -crossplay launch parameter advertises the server on the platform network rather than Steam alone. In practice, players coming from another platform can then join, which is impossible otherwise.

It is the only route to that: there is no configuration trick or mod that achieves the same thing.

What it changes for connecting

This is the part most people discover afterwards. In crossplay mode:

• Direct IP connection no longer behaves the same. The server is identified by a session ID rather than an address and port pair.
• Some Steam players find the server less easily in the community list, when they had no trouble before.
• Favourites your players saved can stop working the day you switch, producing a server that looks gone while it is running perfectly.

None of this is fatal, but it is worth telling your group before you flip it rather than after.

Deciding based on your group

The question is not whether crossplay is better, it is whether you have non-Steam players.

• All-Steam group: leave it off. You keep direct connection and easy discovery, and lose nothing.
• At least one player elsewhere: turn it on. There is no alternative, and the drawbacks above are minor next to excluding them.
• Not sure: start without. Crossplay can be enabled later without touching the world or the characters.

Mods and crossplay

A modded server requires every client to run the same mods. That rule is independent of crossplay, but it combines badly with it: mod distribution is not uniform across platforms, and you can end up with players who technically cannot line up.

In practice a heavily modded server open to crossplay is a combination that demands discipline on the administration side.

Switching without breaking anything

Enabling or disabling crossplay touches neither the world, nor the characters, nor the saves: it is a launch parameter, not a world property. A restart is enough, and you can reverse it the same way.

The only real precaution is warning your players and giving them a way back in afterwards. On our Valheim hosting the setting changes from the panel and applies on the next restart, with no file editing.