Based on the full-release announcement and official patches through 1.0.15. Menu labels and connection behavior may change in later builds.
Host a world
The official announcement says the host can use a single-player save. Choose the room settings before inviting friends: Standard co-op defaults to four players and can be adjusted up to eight; Horde Mode supports up to four.
NoteDecide on a password and friendly-fire settings together before starting.
Join your friends
Supported routes include a six-digit room code, the public room list, a Steam friend invite and LAN. Guests can create a character or bring an existing single-player character. The game can fall back to its official relay when a direct connection is unavailable.
NoteUse an invite or a private room when playing with a specific group.
Understand saves and mods
The host manages saving and loading for a shared world. Patch 1.0.14 clarified this in the guest pause menu and changed how earned levels and skills behave when an older save is loaded; inventory still comes from that save.
NoteThe launch announcement says host mods sync to joining players. Agree on the mod set before a session.
Troubleshoot a room code
Patch 1.0.12 added a message when a room code has not arrived after 20 seconds and lets the game keep retrying. The announcement names packet loss and interference from network accelerators or security software as possible causes.
NoteFor every room-code symptom and the order to check them in, see room code not working.
Check recent co-op fixes
Patches 1.0.12–1.0.15 address connection, inventory and synchronization problems. If a guest sees missing equipment or an inconsistent interaction, compare the installed build with the official notes before repeating the action.
NoteHorde Mode does not save in the same way as a Standard world. Check the mode before treating a session as persistent.
Sources & references
Reviewed against published documentation on 12 Nov 2026. Advice is editorial unless identified as a documented game behavior; no in-game testing is claimed.