Mods transform Minecraft from a sandbox game into whatever you want it to be—tech automation, magic systems, new dimensions, or massive creature overhauls. But getting those mods working on a multiplayer server? That’s where most people hit a wall.
The process isn’t complicated once you understand the basics, but there are specific steps you need to follow and common mistakes that’ll waste hours of your time. Here’s exactly how to get mods running on your Minecraft server.
What You Need Before Installing Mods
Quick Answer: To use mods on a Minecraft server, you need a mod loader (Forge or Fabric) installed on both the server and all players’ clients, matching Minecraft versions across everything, and enough RAM allocated to handle the additional processing load—typically 4GB minimum for modded servers.
Before you touch any mod files, verify three things:
- Minecraft version compatibility – Your server, mod loader, and every mod must match the exact same Minecraft version (like 1.20.1, not just “1.20”)
- Mod loader choice – Most mods use either Forge or Fabric. They’re not interchangeable, so pick based on which mods you want
- Server resources – Modded servers need significantly more RAM than vanilla. Budget at least 4GB for light modpacks, 6-8GB for medium ones, and 10GB+ for heavy automation mods
Understanding the difference between plugins and mods is crucial here—plugins run on Bukkit/Spigot servers and work server-side only, while mods require both server and client installation.
Installing a Mod Loader on Your Server
The mod loader acts as the foundation that makes mods work. Without it, your server won’t recognize mod files at all.
Setting Up Forge
Forge dominates the modding scene with the most available mods, especially for older Minecraft versions and large modpacks.
- Download the Forge installer from the official Forge website for your exact Minecraft version
- Run the installer and select “Install Server”
- Choose your server directory as the installation location
- After installation, locate the new forge jar file (named something like “forge-1.20.1-47.2.0.jar”)
- Edit your server startup script to launch this forge jar instead of the vanilla server jar
- Start the server once to generate the “mods” folder
Setting Up Fabric
Fabric loads faster and uses less memory than Forge, making it popular for performance-focused servers and newer Minecraft versions.
- Download the Fabric installer from fabricmc.net
- Run the installer and select “Server” tab
- Choose your Minecraft version and server directory
- Click “Install” to generate the fabric-server-launch.jar
- Start the server using this launch file to create the “mods” folder
Most hosting providers let you switch to Forge or Fabric servers with one click through their control panel, which handles the installation automatically. GameTeam.io offers pre-configured Forge and Fabric servers starting at $1/GB—currently 20% off for new users.
Adding Mods to Your Server
Once your mod loader is installed and you’ve started the server at least once, you’ll see a “mods” folder in your server directory. This is where everything goes.
The Installation Process
Download your chosen mods from trusted sources like CurseForge or Modrinth. Always verify the mod matches your Minecraft version and mod loader type.
Drop the mod files (they’ll be .jar files) directly into the mods folder—no extraction needed. If you’re working with a complete modpack, the server files usually come with all mods pre-packaged in the correct folder structure.
Restart your server. Check the console logs carefully—they’ll show which mods loaded successfully and flag any conflicts or missing dependencies.
Handling Mod Dependencies
Many mods require library mods to function. Common ones include:
- Fabric API – Required for almost all Fabric mods
- Architectury API – Enables cross-platform mods
- JEI (Just Enough Items) – Recipe viewer that many mods integrate with
- Patchouli – Powers in-game guidebooks for complex mods
Your console will explicitly tell you if a dependency is missing. Download the required library mod and add it to your mods folder, then restart.
Client-Side Setup for Players
Here’s what trips people up: players need the exact same mods installed on their client to join your server. Missing even one mod will cause connection failures.
The cleanest approach is creating a client modpack with the same mod list. You can do this through CurseForge or manually by providing players with:
- The correct Forge or Fabric installer for their launcher
- A zip file containing all the mods from your server
- Clear instructions on where to place the mods folder (in their .minecraft directory)
Some mods are server-side only and don’t need client installation, but these are rare. When in doubt, include it in the client pack.
Performance Optimization for Modded Servers
Modded servers eat resources. The more complex the mods—especially automation mods like Create or tech mods with constant processing—the more strain on your server.
RAM Allocation
Allocate RAM based on your mod count and type:
| Server Type | Recommended RAM |
|---|---|
| Light mods (5-20 mods) | 4-6GB |
| Medium modpacks (20-50 mods) | 6-8GB |
| Heavy modpacks (50+ mods) | 8-12GB |
| Create or automation-focused | 10-16GB |
If you’re running something intensive like a Create mod server, understand that mechanical networks process continuously, demanding significantly more resources than content-addition mods.
Performance Mods
Add these optimization mods server-side to improve performance:
- Lithium (Fabric) – Optimizes game physics and mob AI
- Phosphor (Fabric) – Improves lighting engine performance
- Starlight – Rewrites lighting engine for better chunk loading
- FerriteCore – Reduces memory usage
- AI Improvements (Forge) – Optimizes entity pathfinding
Common Problems and Fixes
Mod Version Mismatches
If players can’t connect, the first thing to check is mod version alignment. Even minor version differences (like 1.4.2 vs 1.4.3 of the same mod) can cause connection failures. Export your server’s mod list and compare it against what players have installed.
Chunk Loading Issues
Modded servers struggle with chunk loading more than vanilla. Install a chunk-loading mod like FTB Chunks or Chunk Loaders to keep important areas active, especially for automated farms and machinery.
Config File Conflicts
Mods generate config files in the “config” folder. Sometimes default settings conflict with other mods or cause performance issues. Check mod documentation for recommended config changes, especially for world generation mods that need to be configured before world creation.
Server Crashes on Startup
Read the crash report—it’ll point to the problematic mod. Common causes include:
- Wrong Minecraft version for a mod
- Missing core library or dependency
- Incompatible mods that modify the same game systems
- Corrupted mod file (redownload it)
Updating Mods Safely
Never update mods mid-game on an active world without backups. Some updates change item IDs or remove content, which can corrupt your world.
The safe update process:
- Back up your entire server directory
- Test the updated mod on a separate test server with a copy of your world
- Verify players can connect with the updated client mods
- Check that existing modded items and blocks still work
- Only then update your production server
For major modpack updates, read the changelog carefully. Some updates require world resets or specific migration steps.
Frequently Asked Questions
Can I add mods to an existing vanilla world?
Yes, but with caveats. Mods that add new blocks, items, or mobs work fine. Mods that change world generation only affect newly generated chunks. Mods that alter core mechanics might cause issues with existing builds.
Do all players need every mod installed?
For most mods, yes. Server-side only mods (usually optimization or administration mods) don’t require client installation, but content mods absolutely do. If a mod adds blocks, items, or changes gameplay, players need it.
How many mods can a server handle?
It depends more on what the mods do than how many you have. Twenty lightweight content mods might run better than five heavy automation mods. The limiting factor is usually RAM and CPU usage during chunk loading and entity processing.
Can I run Forge and Fabric mods together?
Not natively. You’d need a compatibility layer like Sinytra Connector, but it’s experimental and doesn’t support all mods. Pick one mod loader and stick with it for stability.
Why does my modded server lag but vanilla runs fine?
Mods add processing overhead—new entities, complex crafting systems, additional world generation, and constant calculations for machinery. Increase your RAM allocation, add performance optimization mods, and consider limiting chunk loading areas for automated systems.
Getting Started with Your Modded Server
Start small. Pick 10-15 mods that work well together rather than throwing 100 mods at your server immediately. Test everything with a few friends before opening to a larger group. Monitor your server’s performance and adjust resources as needed.
The modding community constantly creates new content, so your server can evolve over time. Just remember: matching versions, proper mod loader installation, and adequate resources are the three pillars of a stable modded server. Get those right, and you’re set.
