How to Make a Modded Minecraft Server (Forge, Fabric and CurseForge Modpacks)

You and a friend have a modpack you love, or a handful of Forge or Fabric mods, and now you want one shared world. It's the same question that keeps turning up on r/CurseForge: "My friends and I are trying to play the Create mod, with the JEI addon, and we can't figure out how to make our own server." Here's how to make a modded Minecraft server without an evening of red error text.

The short answer: if you play a CurseForge modpack, grab its server pack from the pack's Files tab, run it, accept the EULA, and have everyone install the exact same pack version. If you're running your own mod list, set up a Forge or Fabric server, put the mods in its mods folder (plus Fabric API on Fabric), and keep the client-only stuff off it. But first, the one rule that breaks more modded servers than anything else.

The rule first: everything has to match

A modded server only works when the server and every player agree on three things: the Minecraft version, the mod loader (Forge, NeoForge or Fabric), and the loader version. Mods are built for one loader. A Forge mod won't load on Fabric, and a Fabric mod won't load on Forge. One hosting knowledge base puts it bluntly: "this is not a version mismatch you can work around, it is a different set of hooks into the game."

The mod lists have to match too, with one exception: client-only mods stay off the server. Shaders, minimaps, inventory tweaks and other visual or UI mods do nothing for a server. At best they're dead weight; at worst one stops the server from starting. The rule that keeps you sane: only put mods on the server that are marked as working server-side, and keep everyone's mod set identical apart from those client-only extras.

Still torn between plugins and mods? My Paper vs Fabric breakdown covers that split.

What you need before you start

• The exact versions. Write down the Minecraft version, loader and loader version your pack or mods are built for.
• Java. Fabric's install guide pairs Minecraft 1.17 to 1.20.4 with Java 17, and 1.20.5 onward with Java 21. On a much newer Minecraft release, check the loader's own page for what it wants.
• Enough RAM. Modded eats more than vanilla (more below).
• Official downloads only. Loaders from their own sites, mods from CurseForge or Modrinth. My Minecraft server software comparison lists the official download page for Fabric, Forge and NeoForge.

How to make a modded Minecraft server with CurseForge

The normal "download" button on a CurseForge modpack gets you the client bundle. What you want for the server is the server pack, a separate download that strips out the client-only mods and adds a server launcher. CurseForge's own guide for pack authors describes it as "a specially prepared version of your modpack that allows it to be run on a multiplayer server."

1. Open the modpack's page on CurseForge and go to the Files tab.
2. Pick the exact version your group plays, then look under Additional Files. That's where pack authors upload the server pack.
3. Download it and extract it into its own empty folder.
4. Run whatever setup it ships with. Many Forge packs include the Forge installer or a ready-made .bat or start script that finishes the install for you.
5. Accept the EULA. The server won't boot until eula.txt says eula=true, same as vanilla.
6. Start it up and share the address.

What if the modpack has no server pack?

It happens. Some CurseForge packs have no server files at all. Then you build the server yourself: install the pack's loader at the exact version the pack uses (Forge or Fabric, below) and add the mods one by one, skipping the client-only ones.

How to make a Forge server

1. Download the Forge installer for your exact Minecraft version from the official Forge download page.
2. Run it and choose Install server. On a machine with no desktop, run java -jar forge-<version>-installer.jar --installServer instead.
3. Put your mods in the server's mods folder. Server-side mods only.
4. Set eula=true in eula.txt.
5. Start the server. The Minecraft Wiki's "Setting up a Minecraft Forge server" tutorial walks through the launch step if you get stuck.

How to make a Fabric server (and why Fabric API goes on it too)

There are two ways. I'd take the simple one.

The simple way: the Fabric Server Launcher

1. On Fabric's server download page, pick your exact Minecraft version and loader version and download the Fabric Server Launcher jar.
2. Drop it in an empty folder.
3. Run it with java -Xmx2G -jar <file> nogui. The 2G is the memory you're handing the server, and a modded server almost always wants more, so raise it to match the RAM section below.

The manual way: the Fabric Installer

Run the Fabric Installer, open the Server tab and pick your Minecraft and loader versions. You get a fabric-server-launch.jar plus a libraries folder, and it expects the vanilla server.jar sitting right next to it.

Don't forget Fabric API

This is the one that gets everybody. Fabric API is a separate mod, not part of the loader. Its CurseForge page shouts it: "This is SEPARATE from the Fabric loader! You need both for most mods!" Download it from Modrinth or CurseForge, match it to your Minecraft version, and put it in the mods folder on the server and on every player's game. Leave it off the server and you'll get a missing-dependency error naming fabric-api the moment you start it.

Then add your mods, set eula=true, and start it.

How much RAM does a modded Minecraft server need?

Mojang, Forge and Fabric don't publish a RAM minimum for modded servers. What you'll find are rules of thumb from hosting companies, and they don't fully agree:

My read: for a handful of friends on a light-to-medium pack, start around 4–6GB. For a big named pack, expect to need a lot more. But check the modpack's own page on CurseForge or Modrinth first, because pack authors often post their recommended RAM right there.

How friends join your modded server

Your friends need the identical setup on their end. For a CurseForge pack, that means installing the CurseForge App (it comes through Overwolf), finding the modpack and installing the exact same pack version the server runs. For your own mod list, it's the same Minecraft version, loader, loader version and mods (Fabric API included), minus personal client-only extras.

Then they connect by the server's address, exactly like joining a vanilla server. If someone can't get in, a pack version mismatch is the most common culprit.

How to make a modded Minecraft server for free

If you'd rather not run it on your own machine, Aternos is the free host I'd use for modpacks. You can install a CurseForge modpack straight from its panel. In Aternos's words: "Set your server software to the Modpack you want to use. This will automatically install all included mods and configure the server for that pack." It also lets you pick Forge, NeoForge, Fabric, Quilt or Arclight directly if you're bringing your own mods.

A few catches:

• The pack needs server files. Aternos says packs on Modrinth and ATLauncher always include them, but on CurseForge and TechnicPack you have to check that the pack has server files. If your pack isn't there, Aternos has a suggestion system for requesting it.
• Startup is slower. A modded server takes noticeably longer to start than vanilla.
• RAM isn't a fixed number. It comes from a shared pool.

Minehut's free plan caps you at 1GB of RAM and 10 slots, which is rough for a real modpack. My full guide to free Minecraft server hosting compares Aternos, Minehut, your own PC and Oracle's free cloud tier, sleep timers and all.

Troubleshooting a modded Minecraft server

"Version mismatch" or friends can't connect

Compare Minecraft version, loader, loader version and modpack version between the server and the player who can't join. One of them is off, usually the pack version.

Missing mods or a missing dependency

Every mod that isn't client-only has to be on both sides. On Fabric, the classic version of this is Fabric API left off the server, and the error names fabric-api. Add whatever mod the error names, at the right version.

The server crashes at startup

• A client-only mod is on the server. Pull shaders, minimaps and UI mods out of the server's mods folder.
• A mod is built for the wrong loader. Get the right build or drop it.
• The EULA isn't accepted. Check eula.txt says eula=true.
• The Forge installer failed with "invalid e-tag checksum." Install vanilla first, then Forge on top.