Install a Minecraft modpack from Modrinth

A modpack is a few dozen to a few hundred mods, their configs and sometimes a custom world, tested together for one Minecraft version and one mod loader. Setting that up by hand means hundreds of files. The Modpacks page in the panel does it for you: you pick a pack on Modrinth, pick a version, and the panel downloads and installs the server side of it.

It is a big operation, though. It force-stops your server and reinstalls it, and it can wipe every file first if you ask it to. Read the first two sections before you click anything.

Pick the right server type and plan

Every pack is built for one loader and one Minecraft version. You can see both on the pack's page on modrinth.com, next to its description.

The installer puts the pack's files on your server, but afterwards your server keeps its own type: its startup command and its Java version stay the same. So the type you created the server with has to match the pack:

Our NeoForge server installs Minecraft 1.21.1 and our Forge server installs 1.20.1, because those are the versions most packs on each loader target. A pack for another Minecraft version can still work on the matching loader, but it may need a different Java version, which the panel lets you switch (see Common problems).

Memory is the other half of the choice. NeoForge and Forge servers always get Max's 4.2 GB, which fits light packs and most big "kitchen sink" packs with hundreds of mods. Fabric packs run on Lite or Turbo; a few dozen mods are usually fine on Turbo's 3 GB. Max renews every 30 minutes, so keep the panel open while you play. Many pack pages state a recommended amount of server RAM; if it is well above 4 GB, the pack is too heavy for a free server.

Back up first

Installing a modpack kills the server process straight away, without letting it save. Press Stop yourself first and wait until the console says the server has stopped, so your world is written to disk properly.

Then decide whether you need a copy of what is there now:

• In Backups, click Create backup. Every server has one backup slot, so if you already have a backup you have to delete it first. Download the old one before deleting it if you want to keep it.
• Or download the world folder over SFTP, which the SFTP guide explains step by step.

A backup lives outside the server files, so it survives even if you tell the installer to delete everything. The backups guide covers restoring one.

Install the pack

1. Open your server in the panel. In the sidebar, open the Minecraft group and click Modpacks.
2. In the Filters box, set Provider to Modrinth. The page opens on Feed The Beast, and CurseForge also appears in the list but is not set up on Torchlite, so stick to Modrinth.
3. Type the pack's name in Search. Only packs that Modrinth lists as working on a server show up.
4. Click the pack. In the window that opens, choose the pack version under Select Version. The first one is preselected. The list only shows version names, so compare them with the pack's Versions tab on Modrinth if you need a specific Minecraft version.
5. Under Options, decide on Delete Existing Files (explained in the next section).
6. Click Install Modpack.

The panel sends you to the console, which shows that the server is running its installation process and that most actions are unavailable. A large pack can take several minutes to download. When it is finished, press Start. On the first start a window asks you to accept the Minecraft EULA; click I Accept and the server starts.

Starting begins a renewal period, so keep the panel open. The renewal guide explains the timer.

What the installer replaces and keeps

Behind the scenes, the panel switches your server to a temporary "Modpack Installer" type, runs a reinstall with it, and then switches the server back to its original type. That is why the loader of your server type matters.

Delete Existing Files decides what happens to the files already there:

• On: every file on the server is deleted before the install, including the world, plugins, configs and old mods. Use this for a clean start, or when you replace one pack with another, so mods from the old pack do not stay in the mods folder and clash.
• Off: your existing files stay where they are and the pack is installed on top. Your world survives, but so does everything else, including old mods.

To update a pack later, go back to Modpacks. The Recently Installed list in the Filters box shows your last packs; click one to open its version list again. Back up first, leave Delete Existing Files off to keep the world, and after the update check the mods folder for two copies of the same mod with different version numbers.

Players need the same pack

A modded server only accepts players who run the same mods. Every player needs the same pack, in the same version, installed in their own launcher. The vanilla Minecraft launcher cannot do this on its own; launchers such as the Modrinth App and Prism Launcher can install a Modrinth pack directly by its name.

Tell your players the exact pack version you installed. Once they have it, they launch the pack and join with your server's address like any other server. If they get kicked with a list of mods, their version does not match yours.

Common problems

The pack list is empty

Check Provider. It starts on Feed The Beast, and CurseForge does not work on Torchlite, so switch it to Modrinth. If a pack still does not appear, Modrinth may list it as client-only.

The server crashes with an out-of-memory error

A java.lang.OutOfMemoryError in the console means the pack does not fit in your plan's memory. Pick a lighter pack, or use a NeoForge or Forge server on Max for a big one.

"Unsupported Java Version" pops up

The pack targets a Minecraft version that needs a different Java than your server type ships with. Pick a version in the window and click Update Docker Image, or change it later under Startup → Docker Image.

The console says an error occurred during modpack installation

That message comes from the temporary installer, which means your server was not switched back to its normal type. Ask for help on our Discord and include your server's name.

My world is gone

Delete Existing Files was on. If you made a backup, open Backups and use Restore on it to bring the old files back.