Terraria serverconfig.txt explainedWorld, difficulty, port & slots

Published on August 4, 2026 · last updated on November 3, 2026

Structure of the serverconfig.txt

The file consists of key=value lines and sits in the server directory. You edit it via the config editor in the web interface or via WebFTP/SFTP. tModLoader uses exactly the same format as Vanilla.

worldname=My World
maxplayers=8
port=7777
password=

Load a world or generate one automatically

There are two ways: load an existing world or have a new one generated. For an existing world, set world= to the path of the .wld file (see upload a world). For a new world, use autocreate:

autocreate=3     # 1=small, 2=medium, 3=large
seed=myseed      # optional world seed
worldname=My World

Set the difficulty

The difficulty value determines the world mode:

• difficulty=0 - Classic (normal)
• difficulty=1 - Expert
• difficulty=2 - Master
• difficulty=3 - Journey mode

The value applies when a new world is created automatically. Existing worlds keep the mode they were created with.

Port, slots & password

With port (default 7777), you set the game port - what counts is the port shown in the panel. maxplayers sets the number of slots, password protects joining and motd defines the welcome message. After changes, a server restart is required.

A word about the port, because it regularly causes confusion: 7777 is only Terraria's default. Your server has a fixed address made up of IP and port, both shown in the web interface. Enter the port shown there in the configuration - and give your fellow players both together, in the form 123.123.123.123:7777. Details under join a server.

An empty password= means: anyone who knows the address can join. Terraria has no whitelist in the proper sense; the password is the only built-in protection. How to lock the server down beyond that is explained under make your server private.

All important values at a glance

Why do my changes not take effect?

Almost always, one of three reasons is behind it, and all three are quickly checked:

1. No restart. Terraria only reads the file at startup. As long as the server is running, nothing changes - no matter how often you save.
2. The value only applies at world generation. difficulty, seed and the world size from autocreate are fixed once when the world is created. On an existing world, they have no effect. If you really want to change the mode, you need a new world - see Journey mode.
3. world overrides autocreate. If there is a world under the given path, the server loads it and ignores all generation parameters. That is the most common case when a new world simply refuses to appear.

A fourth, rarer case: spaces around the equals sign. maxplayers = 8 is not read reliably, maxplayers=8 is. Write the lines without spaces and do not put comments after the value - the # for comments belongs at the start of the line.

Frequently asked questions