Server Setup

How to Add Mods to a Minecraft Server

Modding a server is three rules: one loader, jars in the mods folder, every client matched. Get those right and the boot log prints Loading N mods. Get them wrong and it crashes on the offending jar.

How mod loading works

1
Pick one loader
Choose Forge OR Fabric for the whole server. Run the matching server jar once so it builds the config and creates an empty mods folder.
2
Get server-side jars
Download mods built for your exact MC version and loader from Modrinth or CurseForge. On Fabric, always add Fabric API as a dependency.
3
Drop jars in mods
Stop the server, copy each .jar into the server's /mods folder. No nesting, no renaming, keep the .jar extension intact.
4
Start and read the log
Boot the server and watch the console for "Loading N mods". A missing-dependency or version-mismatch crash names the offending jar.
5
Match every client
Players need the same loader, same MC version, and the same client-required mods. Server-only optimizers (Lithium, FerriteCore) don't need a client copy.

server console, fabric-server-launch● running
[main/INFO]: Loading Minecraft 1.20.1 with Fabric Loader 0.15.7
[main/INFO]: Scanning mods directory...
[main/INFO]: Found 6 mod candidates
[FabricLoader/INFO]: Loading 6 mods:
   - fabric-api 0.92.0+1.20.1
   - sodium 0.5.3
   - lithium 0.11.2
   - ferritecore 6.0.1
   - lazydfu 0.1.3
   - modmenu 7.2.2
[Server/INFO]: Preparing level "world"
[Server/INFO]: Loading 6 mods complete
[Server/INFO]: Done (4.812s)! For help, type "help"
Steve joined the game
>  

What you need

Mod .jar files

/mods folder

Fabric API

Matching MC version

Quick answers

?

Forge or Fabric?

Both can't run at once. Fabric is lighter and faster to update; Forge has the deepest mod catalog. Match whatever your chosen mods are built for.

?

Where is the mods folder?

In the server's root directory, next to server.jar and world. It appears automatically the first time you launch the modded server jar.

?

Do I need Fabric API?

Almost always on Fabric. Most mods depend on it. If the log says a mod "requires fabric" then drop fabric-api.jar into the same mods folder.

?

Why does it crash on boot?

Usually a version mismatch (mod built for a different MC version) or a missing dependency. The crash report names the mod and what it expects.

?

Do clients need the same mods?

Yes for content and gameplay mods. Server-side-only mods (Lithium, FerriteCore, Spark) run fine without any client install.

?

Can I use plugins too?

Not on vanilla Forge/Fabric. For Bukkit-style plugins use Paper, or run a hybrid like Mohist if you genuinely need both.

More guides on this site

Guides that go with this one

How to Install a Fabric Server (1.21.4)

Set up a Fabric server step by step: download the launcher, drop in Fabric API, add Lithium and...

How to Fix Mods Not Loading in Minecraft

Fix Minecraft mods not loading or not appearing in-game. Covers mod folder placement, version...

How to Install a Forge Server

Run the Forge installer with --installServer, accept the EULA, and boot a modded Minecraft server. Real...

How to Install Paper on a Minecraft Server

Swap your vanilla server jar for paper-*.jar in five steps. Faster TPS, fewer crashes, and full plugin...

How to Install Plugins on a Minecraft Server

Drop a .jar into the /plugins folder, restart the server, and watch the [PluginName] Enabled line...

How to Survive the First Night in Minecraft

Dusk to dawn in one move: punch wood, throw up a 1x1 dirt-and-log box, drop a torch and a bed. Stop...

Hosting →

Managed Hosting

Skip the setup: a managed server online in minutes.

Database →

Command Reference

Syntax, arguments and examples for every command.

Database →

Every item with its stats, IDs, recipes and uses.

Guides →

More Server & Admin guides

Run a server: setup, hosting, permissions, worlds and crossplay.