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Multiplayer

The launcher has built-in multiplayer: no public IP and no server hosting required to play your singleplayer world with friends.

Quick start

Click Multiplayer in the sidebar to open it.

Host: the person creating the room

  • Select the local instance you want to play on
  • Click Start and create room to get a room code (the launcher starts that instance first)
  • After it starts, remember to use “Open to LAN” on your singleplayer world in game so the multiplayer layer can reach the world
  • The launcher scans local ports; if it finds none, switch to manually enter port
  • Send the room code to your friends
  • Keep the page open and wait for players to join
Already started the instance yourself? Click “Already started the instance manually? Click here” on the page to create the room directly.

Player: the person joining

  • Enter the room code from the host
  • After joining, select your local instance and the launcher compares mods automatically
Multiplayer is built on EasyTier; the component is downloaded automatically on first use, so wait for the download to finish. If you need a custom relay, configure it in Settings → Network settings → Multiplayer nodes.

Mod consistency check

When you join, the launcher compares the host’s mod list against your local instance, item by item: When you have several local instances, the launcher recommends the instance with the largest mod overlap with the host, and the missing list is calculated against it.

Host controls

Inside the room, the host can:
  • View the player list: current online members in real time
  • Kick player: remove a disruptive player from the room (their network identifier is also blocked to prevent automatic reconnection)
  • Rejoin approval: when a kicked player tries to come back, a dialog asks you to confirm. Allow lets them in, deny keeps blocking them. You can also deny silently (no more dialogs)
  • Unban: lift the block from the kicked players list

Troubleshooting connection failures

Virtual network adapter software such as Radmin VPN and Hamachi can conflict with multiplayer. The launcher does not work around them automatically: if connections misbehave, quit such software first and try again. If you need to keep it running, switch to a custom relay node in Settings → Network settings → Multiplayer nodes.