Install the Terralith mod on your server

Terralith rebuilds Minecraft's overworld terrain with about 95 new biomes, from canyons and volcanic peaks to sky islands, using only vanilla blocks. It changes how the world generates, so the one rule that matters is when you install it: before the world exists.

Checked against Terralith 2.6.5 on Fabric 26.3, October 2026.

What you need

• Fabric or NeoForge on Minecraft 26.3. Terralith 2.6.5 is the newest release and carries a 26.3 build for each. The same page lists older builds for 1.21.1, 26.1 and 26.2. Pick the version in JAR Manager and the panel chooses Java for you (Java 25 for 26.x).
• Lithostitched, version 1.8.0 or newer. Terralith's mod build requires it, and Modrinth lists it as a required dependency.
• Fabric API on Fabric. Lithostitched's Fabric build requires it. The install window follows these chains for you.
• Players. Modrinth marks Terralith as optional on the client and required on the server, so players can join without it.

Switch the server to Fabric 26.3

1. Open JAR Manager, under More in the left rail.
2. Set Server software to Fabric and Minecraft version to 26.3, then press Apply change.
3. Leave Take a backup first ticked, press and hold Confirm & reinstall, and wait for the console to finish.

Your world is kept, but configuration files may be reset. Change your Minecraft version or mod loader covers the switch in full.

Install it

1. Open the Mods tab under Content and leave the Modrinth source chip selected.
2. Search for Terralith and press Install. The window lists the add-ons it needs, such as Lithostitched. Choose Install all.
3. Check the Installed view for Terralith, Lithostitched and, on Fabric, Fabric API.
4. Open the Config Editor, set World folder to a new name such as terralith-world, and press Save changes. A new folder means a new world, and the old one stays on disk. If the Config Editor says server.properties does not exist yet, start the server once, stop it, and then set the name.
5. Go to Console, press Start and accept the EULA prompt the first time.

If you want to keep a world you already built, take a backup first and treat the new world as a separate one. Create and restore backups shows how.

Check that it worked

Join and look for terrain you do not recognise. As an operator you can also run these in game, and the game reports coordinates:

• /locate biome terralith:yellowstone
• /locate structure terralith:mage_tower

Settings

The mod build has a config file named terralith.json. It appears in the config folder after the first start, which you can open in the File Manager. The options, with their defaults:

• Custom Structures, on: Fortified Villages, Mage Towers and similar.
• Fog Tweaks, on: changes fog distance and colour in biomes such as swamps and caves.
• Intro Message, on: shows a toast when a new world is created.
• Skylands, on: four season-themed sky island biomes above deep oceans.
• Terrain Slabs, on: stone slabs that smooth the terrain in biomes with stone at the surface.
• Vanilla Stone Generation, off: puts small blobs of granite, andesite and diorite back underground.
• Recipe Changes, off: lets some cobblestone recipes use other stones.

Stop the server before you edit the file, then start it again.

Common problems

• The server stops at start and names lithostitched. Install Lithostitched in the build for your loader and Minecraft version.
• The server stops at start with "Overworld settings missing" and you also run Lithium. In our test, Terralith 2.6.5 with Lithium 0.26.2 on Fabric 26.3 would not start on a new world, and adding mixin.gen=false to config/lithium.properties let the pair start. Each mod started fine alone.
• Fabric complains about fabric-api. Install Fabric API from the Mods tab.
• You added Terralith to a world players already explored. The page advises against it. Point World folder at a new name, or reset the world after a backup.
• Anything else at start. Fix Minecraft mod and plugin load errors shows how to read the log.