How to run a Minecraft modpack server

To run a modpack, open Mods, find the pack in the modpack directory and pick it. The panel sets the right mod loader, game version and Java for you, and keeps the pack pinned so it never updates by surprise. Your friends then install the same pack, at the same version, in a launcher like the CurseForge app, the Modrinth App or Prism Launcher.

Start a modpack from the directory

The modpack directory lists packs from Modrinth and CurseForge that can run on a server, with shelves like “Best for 4 friends”, “Tech” and “Adventure”.

1. Open Mods and go to the modpack directory.
2. Search for the pack, or browse the shelves. Each pack shows how much RAM it needs.
3. Pick the pack and the version. Choose the version your friends will play, which is usually the newest.
4. Choose to start it as a new save, or to replace the world you have. If you replace it, we back up the current world first.
5. Wait for the install. The panel downloads the server files from Modrinth or CurseForge, and sets the loader (Fabric, NeoForge or Forge), the game version and Java.
6. Press Start. The first start of a big pack can take a few minutes, because every mod loads and the world is built. Watch Console until it prints a line starting with Done.

Your old world isn’t lost when you start a pack as a new save. Switch back to it any time in Games.

How much RAM a modpack needs

Modpacks need much more RAM than plain Minecraft. Mod count is a good rough guide, and the pack’s page in the directory shows its own guide.

Add more for bigger groups, lots of exploring and big automated factories. If the server crashes with java.lang.OutOfMemoryError, it needs a bigger plan. See performance for the settings that help most.

What your friends install

Every player needs the same modpack at the same version as the server. The official Minecraft Launcher can’t install modpacks, so friends use one of these free launchers:

The Mods tab has a card that shows what your friends need, with a link to your pack. Send it to them.

In the CurseForge app

1. Open the app and pick Minecraft.
2. Browse modpacks and search for the pack.
3. Open the pack and pick the same version as the server from its list of versions, then install it.
4. Press Play, then join castle.play.wilderack.com from Multiplayer.

In the Modrinth App

1. Open the app and search for the pack under modpacks.
2. Open the pack’s versions list and install the version that matches the server.
3. Press Play, then join from Multiplayer.

In Prism Launcher

1. Click Add Instance.
2. Pick Modrinth or CurseForge on the left, depending on where the pack comes from.
3. Search for the pack, choose the matching version and confirm.
4. Launch the instance and join from Multiplayer.

Some CurseForge packs include mods whose makers don’t allow other launchers to download them. Prism then asks you to download those few files in your browser.

Pinned versions and updates

Modpacks never update on their own. A pack update can change or remove mods, and that can break blocks, items or whole parts of a world.

When a new version of your pack comes out, the panel tells you:

1. Read the changelog it shows. Look for words like “world reset needed” or “not compatible with old worlds”.
2. Pick a time when nobody is playing.
3. Start the update. We take a backup first.
4. Tell your friends to update the pack to the same version in their launcher before they join.

If the update goes wrong, restore the backup from before the update in Backups. Players who updated their launcher must go back to the old version too.

To try an update without risk, duplicate your save in Games first and update the copy.

Packs that aren’t in the directory

You can run a pack by hand if its makers publish server files:

1. Find the pack’s server pack. On CurseForge it’s a separate download in the pack’s files, often called “Server Pack”. Not every pack has one.
2. In Settings, set the Server type and Game version the pack needs (for example NeoForge on 1.21.1). Match the loader’s own version too, where the pack names one.
3. Stop the server, then upload the server pack’s mods and config folders, plus any others it has (like kubejs or defaultconfigs), through Files or SFTP.
4. Start the server and watch Console.

You don’t need the pack’s start script. The panel starts the server and sets its memory from your plan.

When something goes wrong

• Friends get a list of missing or mismatched mods: their pack version doesn’t match the server’s. See modded server errors.
• The server crashes on start: open Console. The crash helper card often names the mod and has a fix button.
• Bedrock friends can’t join: most packs add content that Bedrock can’t show. See Bedrock crossplay.