How to run a Calamity Mod server on free Terraria hosting

What we tested

On 1 November 2026 we installed Calamity on a ChunkArc QA server with the same 2 GB of RAM as a Free Beta Terraria server. Times depend on Steam Workshop and on how busy the platform is, so treat them as an example.

Create a tModLoader server

1. Open Manage, choose Terraria and select tModLoader. Vanilla and TShock cannot load Calamity. The Terraria setup guide covers the creation form, region and address.
2. Wait for the installation to finish and make sure the server is stopped. Mods can only be applied while it is stopped.
3. If you are bringing an existing world, back it up first and keep the matching .wld and .twld files together. The world import guide explains the upload.

Install Calamity from the catalogue

1. Open Plugins & mods and choose Explore. Search for Calamity Mod and open Details to check the author and the requirements.
2. Choose Prepare preview and wait. Large mods take longer: in our test the Calamity Mod preview took about 5 minutes. You can leave the page while it runs.
3. Open the preview and check the files, dependencies and warnings. Select the confirmation checkbox and choose Apply changes. Applying Calamity Mod took about 2 minutes 36 seconds in our test.
4. Install Calamity Mod Music the same way if you want it. In our test, installing one did not add the other automatically, so install each one you want.
5. Start the server yourself and read the console. In our test “Server started” appeared 48 seconds after the start.

Is 2 GB of RAM enough for Calamity?

For a small world with no players, yes: the server used about 961 MiB right after startup. That is a single measurement, not a ceiling. Memory use grows with players, world size and every extra mod, and we did not test players joining or a long session.

Start with Calamity alone, add other large mods one at a time and check the console after each start. Larger worlds and heavier modpacks may need more memory than the Free Beta provides.

What each player needs

Every player needs tModLoader and the same mods in the same versions as the server: at the time of our test, Calamity Mod v2.2.4 and Calamity Mod Music v2.1. A regular Terraria client cannot join a tModLoader server.

Steam can update a mod on a player’s PC while the server keeps the version you installed. Mods are not updated automatically on the server: when a new version comes out, check Installed in Manage, where an update is offered for mods installed from the Workshop.

Existing world or a new one?

Our test loaded an existing world created before Calamity was installed, and it started. Some content added by a mod may only appear in newly generated worlds; check the mod’s own page before deciding. Keep a backup of the world either way.

If the preview or startup fails

Read the message shown in Manage; the technical code is under Technical details. If the server no longer starts after a change, use the recovery copy that Manage keeps from the last mod operation to restore the previous mods, configurations and worlds. In our test the restore took about 2 minutes 20 seconds.

Send support the error text and the time of the operation, never passwords or tokens. Catalogue and malware checks cannot guarantee that every mod is safe or compatible.