How to Play Core Keeper Multiplayer: Hosting, Joining and Game IDs

Summary

How to play Core Keeper multiplayer

The host shares a Game ID
Once in the world, open the pause menu, choose Copy game ID and send it to the players who want to join.
Players enter the ID
On the title screen, choose Join Game, then Join With Game ID, and paste the ID.
No public server browser
The game's join options are a Game ID, an IP address or a friend invite; there is no list of public sessions. The title screen links to the official Core Keeper Discord server, where players look for groups.

How to play multiplayer on PC (Steam)

Host

Choose a world and a character and start the game.
Open the pause menu and choose Copy game ID.
Send the Game ID to the players who want to join (Discord, chat, etc.).

Joining players

On the title screen, choose Join Game and then Join With Game ID.
Enter the Game ID you received. If the game asks you to Enter Password, enter the one the host gave you.
Select character and join. You bring your own character into the host’s world.

Friends can join without an ID: turn on Allow friends to join without Game ID, and your friends can join directly.
Playing with another PC store: the host sets the crossplay option to All PC players instead of Steam only (crossplay).
Joining by IP: Join With IP lets you enter the host's IP address and port directly.

How to play multiplayer on PS5, PS4, Xbox and Switch

Invite friends: on consoles, use Invite Players in the game to invite your friends on that platform. The game shows “Invite to (name) sent successfully” when it worked.
Only the same console family can play together: PS4 with PS5, Xbox One with Xbox Series, Switch with Switch 2. Consoles cannot connect to PC.
Online services: the PlayStation Store page says PS Plus is required for online play. On other consoles, check that platform’s online service requirements.
Player count: up to 8 players on PlayStation and Xbox, up to 4 on Switch (the Switch 2 Edition allows 8 online). Details: How many players?.

Host tools: ban, admins and password

Ban: the host and admins can ban players. Banned players are listed under Banned players, and they see “You cannot join this session because you have been banned by a session admin.”
Change the ID: Refresh password and game ID makes a new password and Game ID so the old ones stop working. The game confirms that this does not affect any progress, and players who are already connected are not thrown out.
Hide the ID: when streaming, use Hide game ID so it is not shown on screen.
Admins: the host can give other players admin privileges (Admin players). Players without them get “You don't have permission…” when they try to ban players or refresh the ID.

Can you play multiplayer with strangers?

The game has no matchmaking or list of public sessions. You can only join with a Game ID, an IP address, or an invite from a friend.

To play with new people, find a group on the official Discord (the title screen has a Join the Core Keeper Discord Server link) or a similar community and share Game IDs there. Anyone who knows your Game ID can join, so set a password when sharing it with strangers and refresh the ID afterwards.

PvP in multiplayer

PvP is off when a world starts. The host or an admin turns player-versus-player combat on and off with Enable PvP / Disable PvP: in the pause menu this is the fist icon under the Game ID, and a crossed-out fist means PvP is off.

Teams: players are split into PvP teams in the connected players panel. Names shown in the same color are on the same team and cannot hurt each other.
Free-for-all: teams do not have to be the same size, and giving every player their own team turns the session into a free-for-all.
Who can change teams: only the host or an admin can move other players to another team.

What happens to saves and progress in multiplayer?

The world belongs to the host: buildings, defeated bosses and so on are saved in the host’s world.
Characters belong to each player: a joining player picks one of their own characters, and it stays theirs.
Use the same version: if the host and the joining player are on different game versions, “Game version mismatch” appears with the host's version, and you cannot join. A character created in a newer version can't be loaded in an older one.

Menu and message names are the game's own English text (Core Keeper 1.3.0.6). Which consoles can play together and PS Plus come from the platform holders' and publisher's information (see the platform pages). What refreshing the ID does to connected players and the player counts come from the publisher's support and community guidelines pages (Fireshine Games); the PvP icon, default and team colors from the Explorer's Guide (1.3 update, p.89), as collected on the Core Keeper Wiki (Fandom) page “Multiplayer” (CC BY-SA 3.0).

More on platforms and multiplayer

Unless a note on the page says otherwise, numbers are read from the game files of Core Keeper 1.3.0.6 (prefabs, configuration files, drop tables and the game's program) and calculated by this site, including upgraded (per-level) values, sell prices and mana costs. Names and descriptions are the game's official English text. Only reinforcing materials, minion and pet attacks and some food values are based on the Core Keeper Wiki (Fandom) data (CC BY-SA 3.0). Core Keeper and its images are © Pugstorm. This is an unofficial fan site.