Terraria server setup with mods (tModLoader)

Modded Terraria is a completely different game. Calamity adds 25+ bosses, Thorium expands class options, and hundreds of smaller mods bring new items, biomes and quality-of-life features. tModLoader is the mod framework that makes it all work, and a dedicated modded server lets your group play together around the clock.

Requirements

• RAM: 1 to 2 GB for vanilla Terraria, 2 to 4 GB with heavy mods like Calamity.
• CPU: single-threaded; one fast core is enough.
• Port: 7777 TCP (default).

Installation

1. Select Terraria with tModLoader in the game panel, or install via SteamCMD on a VPS (app ID 1281930).
2. Start the server once to generate the default configuration files.
3. Edit serverconfig.txt:

   world=worlds/MyWorld.wld
   port=7777
   maxplayers=8
   password=yourpassword
   

Adding mods

1. Open tModLoader on your PC and subscribe to mods in the Mod Browser (e.g. Calamity Mod, Thorium Mod, Boss Checklist).
2. Mods download to %userprofile%/Documents/My Games/Terraria/tModLoader/Mods/.
3. Upload the .tmod files via SFTP to the server's Mods/ folder.
4. Also upload enabled.json (the list of active mods).
5. Restart the server.

The server and every client must run exactly the same mod versions.

World generation with mods

Some mods (Calamity, Thorium) add biomes and structures during world generation. You need to generate the world with mods enabled:

1. Start the server without an existing world file.
2. The server generates a new world that includes mod content.
3. Alternatively, generate the world on your PC with tModLoader and upload the .wld file.

Can I add mods to an existing world?

Item and recipe mods work on existing worlds without issues. Mods that add biomes and structures only affect newly generated terrain. For Calamity, a fresh world is recommended to get the full experience.

My server crashes on startup with mods

Check the server log for the mod name in the error. Common causes include incompatible mod versions, missing dependencies, or insufficient RAM. Calamity alone needs at least 2 GB of memory.

Terraria servers are available on the game hosting packages at HostValues.