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Terraria: server config, worlds, and tModLoader mods

Set difficulty, player cap, and a password in serverconfig.txt, upload or create worlds, and switch to tModLoader when you want mods.

Last updated July 16, 2026

A Terraria server is configured by one file — serverconfig.txt — and plays whatever world you point it at. This guide covers both, plus switching to tModLoader when you want mods.

Configure serverconfig.txt

  1. Open your server and click File Manager.
  2. Open serverconfig.txt in the root folder.
  3. Change values, save, then restart from the Console tab.

The settings that matter:

worldname=My World
difficulty=1
maxplayers=8
password=
motd=Welcome to our ServerPrism server!
autocreate=3
seed=
Setting Meaning
worldname Name of the world to load or create.
difficulty 0 Classic, 1 Expert, 2 Master, 3 Journey.
maxplayers Player slots (keep it sane for your plan).
password Set a value to make the server private; leave blank for open.
autocreate World size when auto-creating: 1 small, 2 medium, 3 large.
motd Message players see when they join.
seed Optional world seed for a new world.

Don't change port unless you know your allocation — the panel sets your game port. Use the Console/Network tab to confirm it.

Worlds

Worlds are .wld files under the server's world folder (commonly .local/share/Terraria/Worlds/ or the path shown in the console on boot).

  • Auto-create: if the worldname world doesn't exist, the server creates it using autocreate/difficulty/seed on first boot.
  • Upload an existing world: upload your .wld (and its .twld companion) via SFTP or the File Manager into the worlds folder, then set worldname to match the file name (without .wld) and restart. See File Manager & SFTP.

Add mods with tModLoader

Vanilla Terraria servers can't run mods — tModLoader is a separate server type for that.

  1. Make sure your server is running the tModLoader version (on the Startup tab, or reinstall as tModLoader). Mods and worlds are not cross-compatible with vanilla.
  2. Subscribe to / download mods from the tModLoader Mod Browser or in-game, then enable them.
  3. Server-side, mods go in the Mods/ folder and are listed in enabled.json. The easiest route is to configure the mod list in single-player first, then upload the Mods/ folder to the server.
  4. Every player must have the same mods enabled to join.

Common issues

  • Changes ignored: you didn't restart, or edited the wrong serverconfig.txt (there's one in the root).
  • "Password incorrect": password is set — share it or clear it.
  • World won't load: the worldname doesn't match the uploaded .wld file name, or the .twld companion is missing.
  • Mods don't work: you're on the vanilla server, not tModLoader, or clients don't have the same mods enabled.