tModLoader Server Hosting

What is a tModLoader server, and how is it different from vanilla?

tModLoader is the community mod loader for Terraria, distributed free on Steam as its own app for anyone who owns the base game. A tModLoader server is its dedicated server build, running your chosen mod list in a world that stays online whether or not you are playing.

The biggest difference from vanilla is on the player side: everyone connects with the tModLoader client rather than regular Terraria, and the server and players must be on the same tModLoader version. Steam offers stable and preview branches, so a friend who opted into preview will not get into a stable server until they switch back.

tModLoader also runs on its own release schedule. When Terraria itself updates, it can take months for tModLoader to follow; after the 1.4.5 update, stable tModLoader stayed on its 1.4.4 base for a long time. That means your modded world may not have the newest vanilla content right away, but mods like Calamity and Thorium are built for whichever base tModLoader is on.

Modded data lives in separate files: .twld for worlds and .tplr for characters.

How do you install mods on the server?

The reliable method is to copy a mod list you already know works on your own PC. In tModLoader, open Workshop, then Mod Packs, and save your currently enabled mods as a new mod pack. The exported folder contains enabled.json and install.txt, and enabled.json is the file the server uses to decide which mods are active.

On the server, upload the .tmod files into the Mods folder and place enabled.json next to them. A mod that sits in the folder but is missing from enabled.json will not load, and that includes mods you built locally.

On first launch, the console shows each mod loading in turn. With a long list this can take several minutes, so do not restart just because the console goes quiet. If a mod fails, the console usually names the mod and the missing dependency responsible. Some mod settings are server-side and apply to everyone, while client-side settings stay on each player's machine.

How much RAM does a modded Terraria server need?

It depends almost entirely on your mod list. A small group running lightweight helpers such as Magic Storage, Boss Checklist and Recipe Browser plays comfortably on Silver 6GB, which is the minimum we recommend for tModLoader.

A content mod the size of Calamity, which adds hundreds of items, enemies and bosses, changes the picture. For Calamity plus a few helper mods and four to ten players, Gold 8GB is the balanced choice. Running Calamity and Thorium together, on a large world with busy events, is where Platinum 10GB or Diamond 12GB starts to make sense.

Kitchen-sink packs with dozens of mods and communities of 20 or more players belong on Emerald 16GB or Xtreme 32GB. When memory runs out, tModLoader usually crashes while loading mods or opening the world, so an out-of-memory error in the console is a clear sign to upgrade. Single-core speed still matters as much as RAM, because the world simulation remains largely single-threaded.

How do players get the mods and join?

Players launch tModLoader from Steam, choose Multiplayer and Join via IP, and enter the server's IP address and port from your panel. If they are missing a mod or have a different version, tModLoader tries to sync them to the server's list as they connect, downloading what is missing and reloading mods.

That sync works, but it can be slow for large lists. A smoother approach is to put every server mod into a Steam Workshop collection and share the link. Players hit Subscribe to All, launch with the same list already enabled, and their first connection takes seconds instead of minutes.

When someone cannot connect, it is nearly always one of three things: their tModLoader version differs from the server's, a mod was updated on the server but not on their side, or they launched regular Terraria by mistake. With the server in İstanbul, players in Türkiye get low latency, and friends elsewhere in Europe and the Middle East generally connect smoothly too.

Mod updates, removals and common problems

The riskiest moment on a modded server is a mod update. Large content mods occasionally rebalance items and bosses, and now and then an update does not play nicely with an existing world. Take a backup from the panel first and run the update while nobody is online.

Removing a mod does not immediately wreck a world. In most cases tModLoader keeps the removed mod's items and tiles as placeholders and restores them if the mod is added back. Even so, swapping content mods mid-playthrough muddles progression, and starting a fresh world is cleaner when you add a major new mod.

If the server crashes during startup, read the last lines of the console; they usually point to a missing dependency or a mod that is not compatible with your tModLoader version. In-game stutter, on the other hand, usually traces back to oversized mob farms, piles of dropped items or several events running at once. Reduce that load before you start cutting mods from the list.