Terraria gives you two ways to play with other people, and the choice between them is usually made by accident (whichever button was closer) and then regretted around the time somebody wants to play while you are out.
The official Terraria wiki documents the server and the multiplayer options. This is the practical difference.
Host and Play is a server inside your game
When you choose Host and Play, your game client starts a server and joins it. The world lives on your machine, and everything works until you close the game.
That is the whole limitation and it is a large one. Your friends cannot play without you. Your machine's performance is shared between rendering the game and running the world. And the world file is wherever your Terraria install put it, which is not where you will look for it later.
For a group of three who always play together, this is fine and always has been. For anything else it is a decision that quietly caps what the group can become.
The dedicated server is a separate program
The dedicated server has no graphics and no player. It loads a world, listens on a port, and keeps running whether or not anyone is connected.
It is also small enough to run on almost anything. Terraria's server is not demanding by modern standards, which makes it one of the few games where a cheap box genuinely is enough — a rare case where the hosting cost question has an easy answer.
The trade is that you now have a server: something that needs starting, updating, backing up and occasionally restarting.
The port, and the part people get wrong
Terraria uses a single port for everything. There is no separate query port, which makes the firewall side simpler than most games.
What is not simpler is that the server binds to it and expects to be reachable directly. Behind a home router that means forwarding; behind carrier-grade NAT it means it will not work at all no matter what you forward, and the answer is a hosted box — the same wall anyone meets when hosting from home.
tModLoader is a different server
If you want mods, you do not run the Terraria server with mods added. You run tModLoader's server, which is a separate program with its own version numbers.
Two consequences follow, and both catch people:
Every player needs the same mod list at the same versions. A mismatch is a failure to join, not a degraded experience.
A tModLoader world is not a vanilla world. Modded content in the world file has no meaning to the vanilla server, and moving between them is not a supported path. Decide before you build anything you care about.
Backups, because the world is one file
A Terraria world is a single .wld file and its companion. That makes backing it up trivial (copy the file) and makes losing it trivial in exactly the same way.
The failure that actually happens is not disk death. It is a world corrupted by an unclean shutdown, discovered when the server will not load it, at which point the only thing that helps is a copy from before. Terraria writes periodic backups itself, and they are in the same directory on the same disk, which covers one failure mode and not the interesting one.
Copy it somewhere else, on a schedule, and check that the copies are not zero bytes. That is the whole of a backup policy worth having for this game.
Autosave, and the setting worth knowing
The dedicated server saves on a timer and on shutdown. The timer is the one that matters, because the clean shutdown is the case that was already going to be fine.
Running save from the console before anything risky (a mod change, a restart, a config edit) costs a second and removes the window where the last twenty minutes of a build exist only in memory. It is the single most useful console command in the game and most server owners never type it once.
Which to choose
Host and Play if the group is small, plays together, and nobody minds the world being unavailable when one person is out.
A dedicated server the moment somebody asks "can I hop on later?", because that question is the one Host and Play cannot answer, and it is usually the question that decides whether a world lasts a month or a year. That is the same threshold as every other listen server, and Terraria hits it earlier than most because its worlds are long-lived by design.
Published · 3 min read