Install Terraria tModLoader & CalamitySetting up modded Terraria properly

Published on August 4, 2026 · last updated on November 4, 2026

Choose the tModLoader variant

For mods to run, your server has to run on tModLoader instead of Vanilla or TShock. With us, you choose the variant per server - and you are not tied to it: as soon as your server is ready, you find the item Server type in the game server panel and switch there with a click between Vanilla, tModLoader and TShock, without a ticket and without waiting. tModLoader uses the same config format as Vanilla (see serverconfig.txt), but additionally loads mods from the mods folder.

One point is important enough with Terraria to mention up front: the new server type starts on an empty directory. Your world is lost in the process. The confirmation dialog says so too, and you have to confirm it explicitly - still, the rule is: download the .wld first, then switch. How to do that is described under create backups; after the switch, you put it back via upload a world. This is not a quirk of our panel but due to the variants themselves - Vanilla, tModLoader and TShock each bring their own set of server files.

Install mods

There are two ways to get mods onto the server:

• Mod browser / Workshop: on the client, subscribe to and enable the mods you want (e.g. Calamity, Thorium) in the tModLoader mod browser.
• Via FTP: upload the .tmod files and the enabled.json via WebFTP/SFTP into the server's mods folder, so that the server enables the same mods.

After uploading, a server restart is required for the mods to be loaded.

Switching from Vanilla or TShock to tModLoader

The switch itself is one click with us - the preparation is the part you should not skip. This order has proven itself:

1. Stop the server and download the world. Fetch the .wld (and, if present, the .bak) to your computer via WebFTP or SFTP. Backups are self-service throughout with us.
2. Switch the server type. In the game server panel under Server type, choose tModLoader and confirm the note that the directory will be emptied. The reinstallation runs automatically, you see the progress live, and the install log can be opened.
3. Restore the world. Upload the .wld into the world directory again and enter the world name in the serverconfig.txt.
4. Add the mods. Upload the .tmod files and enabled.json, start the server, check in the console what was loaded.

Two expectations should be kept honest: a world that grew in Vanilla or under TShock can be played on under tModLoader - but the mods only place their content where nobody has been yet. And the way back from a modded world to Vanilla does not work cleanly: everything that comes from a mod is then missing. For a different selection, a new world is the more honest way.

Version match is mandatory

The most common mistake with modded Terraria: different versions. The server and all players need the same tModLoader version and exactly the same mods in the same version. Even one deviating mod version prevents joining. So update mods in a coordinated way and restart the server afterwards.

tModLoader 1.4.5: the current state

Vanilla Terraria has been on version 1.4.5 ("Bigger and Boulder") since January 2026, but the stable tModLoader version is still based on Terraria 1.4.4. As of November 1, 2026, there is no tModLoader for 1.4.5 yet, and the team has not given a date. It is working on it and maintains the 1.4.4 version with bug fixes until then. Be careful with sites that name a fixed date: officially, there is none.

In practice, this means: the content of 1.4.5 is not yet available on a mod server, and a world created in Vanilla 1.4.5 cannot simply be played on under tModLoader. If you want mods and the newest content, you have to choose one of the two for now.

As soon as the new version comes out, the usual order applies: back up the world, check whether your mods are already available for 1.4.5, and only then switch. Many mods will need time. If you have a running round, there is therefore no need to switch immediately.

enabled.json: the file that decides

The mods folder contains all .tmod files on the server. But only what is listed in the enabled.json is loaded - a simple list of internal mod names:

[
  "CalamityMod",
  "ThoriumMod",
  "MagicStorage"
]

What matters is the internal name, not the display name from the mod browser. "Calamity Mod" is called CalamityMod internally, without a space. The safest way is therefore to transfer the file directly from the client: there, you have an already correctly filled enabled.json as soon as you have enabled the same mods locally. Copy it to the server together with the .tmod files, and nothing can go wrong.

A mod whose file is present but which is not on the list is silently ignored - no error, no message. That is why a server sometimes starts "without mods" even though all files are in the right place.

Update mods without breaking the world

Content mods reach deep into the world: they add their own ores, biomes, NPCs and items. An update in the middle of a running round is therefore not purely a file matter. Stick to this order and it stays manageable:

1. Stop the server and take a backup of the world. Backups are self-service with us; you fetch the .wld via WebFTP or SFTP - see create backups.
2. Update the mods on the client and start it there once, so that tModLoader writes the new versions.
3. Transfer the new .tmod files and the enabled.json to the server.
4. Start the server and briefly check the world before everyone rejoins.

Removing a mod from a running world is the riskiest step of all: all items and blocks of this mod disappear without replacement, and gaps appear in chests. Once you have decided on a modpack, it is better to keep it until the end of the round - for a different selection, rather create a new world.

Plan RAM for large packs

Vanilla Terraria is frugal, large content mods are not: Calamity and similar packs need noticeably more RAM, several combined mods even more. Plan a larger package for this (L/XL). With us, an upgrade is possible at any time without data loss - world and mods are preserved.

The requirement does not rise linearly with the number of mods, but with what they bring into the world. An interface mod costs practically nothing, a large content mod with new biomes and hundreds of items costs a lot. And it costs more and more the longer the world runs and the more of it has been explored.

Too little memory usually becomes noticeable when changing worlds or entering new areas - the server hangs briefly or shuts down. If this happens reproducibly in the same places, the package size is the cause, not a single broken mod.

Frequently asked questions