How to install Fabric mods on your Minecraft server
Fabric is the lightweight way to run mods on a Minecraft server. It starts quickly, updates soon after each new Minecraft release, and its mod list leans toward performance and quality-of-life changes. Installing mods is simple once you know the three things that cause nearly every problem: matching versions, missing dependencies, and putting server-side and client-side mods in the right place.
Before you start
Check these before you download a single file:
- Your Minecraft version. Mods are built for specific versions. A mod made for 1.20.1 will not load on 1.21, and the server will refuse to start rather than guess.
- Your server type. The server must run Fabric, not Paper, Purpur or Forge. Plugin software does not load Fabric mods. If you need to switch, Paper, Purpur, Fabric, Forge or Vanilla explains the differences and Change your Minecraft version or server type shows how.
- A backup. Take one before changing anything. See Creating and restoring backups.
Step 1: set up the Fabric server
On a managed panel you usually pick Fabric as the server type and choose the version. If you are installing by hand, download the Fabric installer from the official Fabric site, run it in server mode for your Minecraft version, and it produces a launch jar next to a libraries folder. Start the server once so it creates its folders, then stop it.
Step 2: add Fabric API
Almost every Fabric mod depends on a library mod called Fabric API. Download the build that matches your Minecraft version and place it in the mods folder first. If a mod's page lists Fabric API as a requirement and you skip it, the server stops with a message naming the missing dependency.
Step 3: add your mods
Download mods only from their official pages on Modrinth or CurseForge, and choose the file for your exact Minecraft version and the Fabric loader. Then:
- Open the file manager and go to the
modsfolder. - Upload the
.jarfiles. For many files at once, use SFTP. - Restart the server and watch the console until it says it has finished loading.
Add mods in small groups, not all at once. If something breaks, you will know which group caused it.
Which mods go where
Mods fall into three kinds, and the mod's page says which one it is:
| Kind | Needed on server | Needed on player's computer | Examples of what they do |
|---|---|---|---|
| Server-only | Yes | No | Performance fixes, admin tools |
| Client-only | No | Yes | Minimaps, shaders, visual tweaks |
| Both | Yes | Yes | New blocks, mobs, items, dimensions |
Putting a client-only mod on the server is a classic mistake. It can crash the server on startup, because the code it expects, such as rendering, does not exist there. If a mod's page says "client" or "client side", leave it out of the server's mods folder.
Players need the matching mod versions for anything in the "both" row, or they will be refused when they try to join.
Reading the errors
Fabric's error messages are better than most. The usual ones:
- "Mod X requires mod Y": install Y, in the version X expects.
- "Incompatible mod set" or a version mismatch: one mod was built for a different Minecraft version. Check every file's version.
- A crash mentioning a mixin: two mods are changing the same part of the game. Remove the most recently added one and test.
- Nothing happens at startup: you may have the wrong Java version. Newer Minecraft releases need newer Java, as described in My server crashes or won't start.
The first error in the log matters most. How to read your server logs shows how to find it.
Good habits for a modded server
- Keep a list of every mod, its version and where you downloaded it. Updating later is far easier.
- Update the server and clients together. If you update only the server, players with older mods cannot join.
- Remove mods one at a time when tracking a problem, restarting between each.
- Watch memory. Modded servers use more than plugin servers. See Minecraft server out of memory if you see crashes.
Once your mods load cleanly, Pregenerate your world with Chunky is a good next step, because worlds with new terrain mods are especially heavy to explore live.
Still stuck? Open a ticket on Discord - run /ticket in any channel, pick a department, and include your Server ID or Invoice ID so we can jump straight in.