1Download the server launcher
Fabric's server page, fabricmc.net/use/server, offers an Executable Server (.jar) for each Minecraft version. It's a small launcher that downloads Minecraft and the Fabric Loader the first time it runs. For Minecraft 26.3, with Fabric Loader 0.19.5 and installer 1.1.2, it's a 182 KB file named after those three versions.
Pick your Minecraft version
The page starts on the newest release, with the newest stable loader and installer. Loader 0.19.5 ran our 26.3, 26.1 and 1.21.1 servers alike.
Download it into an empty folder
Everything the server makes goes in that folder: the world, the mods and the settings.
Or fetch it from a terminal
The page shows the same curl command as below, for your choice of versions.
# An empty folder for the server
mkdir fabric-server && cd fabric-server
curl -OJ https://meta.fabricmc.net/v2/versions/loader/26.3/0.19.5/1.1.2/server/jar
java -Xmx2G -jar fabric-server-mc.26.3-loader.0.19.5-launcher.1.1.2.jar nogui
# The same with Fabric's installer, in two steps
curl -O https://maven.fabricmc.net/net/fabricmc/fabric-installer/1.1.2/fabric-installer-1.1.2.jar
java -jar fabric-installer-1.1.2.jar server -mcversion 26.3 -downloadMinecraft
java -Xmx2G -jar fabric-server-launch.jar nogui
The installer printed Done, start server by running fabric-server-launch.jar, and left that 616-byte file beside Minecraft's server.jar. Both ways start the same server.
2Start it, and accept the EULA
Minecraft 26.1 and newer need Java 25, 1.21 needs Java 21, and 1.20.1 Java 17. On Java 21, our 26.3 server stopped at once:
Fabric 26.3 started on Java 21
java.lang.UnsupportedClassVersionError: net/minecraft/bundler/Main has been compiled by a more recent version of the Java Runtime (class file version 69.0), this version of the Java Runtime only recognizes class file versions up to 65.0
Class file version 69 is Java 25, and 65 is Java 21. Install Java 25 and start it again.
Run it once
Ours downloaded Minecraft and Fabric's libraries, about 130 MB, in 7 seconds, then stopped with You need to agree to the EULA in order to run the server.
Accept the EULA
Open eula.txt, change eula=false to eula=true, and save it.
Run it again
The log names Fabric: Loading Minecraft 26.3 with Fabric Loader 0.19.5. Ours was ready 7 seconds after it started, and used about 690 MB of memory with nobody on.
Players connect on port 25565. If they're not on your network, port forwarding covers the router and the firewall.
3Add Fabric API and mods
The first start makes a mods folder. Download mods marked for Fabric and your exact Minecraft version, from Modrinth or CurseForge, into it, and restart. Fabric's own page says most mods need Fabric API too, and it's one file.
With Fabric API, Lithium and FerriteCore, our server logged Loading 44 mods. Fabric API alone is 38 of them, itself and its 37 modules, and the loader, Minecraft and Java count too. It used about 670 MB with nobody on.
A mod that needs Fabric API, without it
[15:50:34] [main/ERROR]: Incompatible mods found!
net.fabricmc.loader.impl.FormattedException: Some of your mods are incompatible with the game or each other!
A potential solution has been determined, this may resolve your problem:
- Install fabric-api, any version.
More details:
- Mod 'Chunky' (chunky) 1.5.3 requires any version of fabric-api, which is missing!
Add Fabric API for your Minecraft version.
A mod made for another Minecraft version
- Mod 'Lithium' (lithium) 0.25.3+mc26.2 requires any version between 26.2 (inclusive) and 26.3- (exclusive) of 'Minecraft' (minecraft), but only the wrong version is present: 26.3!
Download the file made for your version. Both errors stopped the server before it loaded the world.
A mod for players' games only is no harm: we added Sodium, and the server loaded the same 44 mods and started, without a word about it. Sodium's own file marks it client-only. On NeoForge the same mod stopped the server: what NeoForge said.
4What players need
It depends on the mods. Our test client, which has no mods at all, tried to join:
| Mods on the server | A player with the plain game |
|---|---|
| Fabric API, Lithium and FerriteCore, on 26.1 and on 1.21.1 | Joined |
| The same, and Nature's Compass, which adds an item, on 26.1 | Turned away: This server requires Fabric Loader and Fabric API installed on your client! |
The message went on to name the mod, under The following registry entry namespaces may be related: naturescompass. So players need Fabric Loader, Fabric API and the same version of every mod that adds blocks, items or mobs. Mods that only change the server, like Lithium, they can go without.
5The one-click way
Playkeeper runs your server on a VPS you rent, and sets up Fabric for you. Install it with one command:
curl -fsSL https://playkeeper.io/install | sudo sh
Choose Fabric and a version
New server lists the Minecraft versions Fabric supports, from 1.20.1 on, with the newest loader, and runs each on the Java it needs. The loader and its libraries are checked against the checksums Fabric publishes.
Add mods from the Mods tab
It lists Modrinth's mods for Fabric and your version, and adds what a mod needs, like Fabric API, with it. Each file is checked against Modrinth's checksum.
Share the mods with friends
Share with friends makes one link to a page with a file for the Modrinth App or Prism Launcher. Server-only mods stay out of it.
Questions
Where do I download the Fabric server jar?
From fabricmc.net/use/server: pick your Minecraft version and download the Executable Server (.jar). It's a launcher that downloads Minecraft and Fabric the first time it runs.
Do I need Fabric API on the server?
For most mods, yes. A mod that needs it stops the server with a message naming fabric-api, and it's one file in the mods folder.
Can players join a Fabric server without Fabric?
Yes, when every mod only changes the server, like Lithium. A mod that adds blocks or items turns them away until they install Fabric and the same mods.
How much RAM does a Fabric server need?
Ours used about 690 MB with nobody on and 2 GB allowed. Players, view distance and mods add to it: the sizing guide suggests a size.
Which Java does a Fabric server need?
The one its Minecraft version needs: Java 25 for 26.1 and newer, 21 for 1.21, and 17 for 1.20.1.
