Core Keeper is a mining sandbox adventure that can be played either alone or with others up to eight friends. Of course, the former can be just as entertaining as the surrounding NPCs can make up your base’s population. But for those who want to bring a friend, Core Keeper allows for both join other worldsas well as invite others to your own.
to invite another player, just press the ESC key on your keyboard. Find them Game ID in the upper left corner of the screen and then copy it. Find the friend you want to share ID with and then just paste it.
Related: Where can I find Tin in the Core Keeper?
As for join another game, you need to retrieve the corresponding game ID. Similar to inviting another player, your friend will have to give you the ID by copying and pasting it from their page. After that easy Copy the game ID after you start Core Keeper and then select enter Game. From here you can Paste the game ID and enter the target world.
For more Core Keeper content, see How to Repair Tools and Weapons in Core Keeper right here on Pro Game Guides.
https://progameguides.com/core-keeper/how-to-start-join-a-multiplayer-game-in-core-keeper/ How to start/join a multiplayer game in Core Keeper