Mods transform Minecraft from a great game into whatever you want it to be—but getting them working on a server is where most people hit a wall. The process isn’t hard once you know the steps, but there’s a specific order to follow, and missing even one step means your players either can’t join or the mods won’t load.
What You Need Before Installing Mods on Your Server
Server mods work differently than single-player mods. You need a modded server software—vanilla Minecraft servers don’t support mods at all. The two main options are Forge and Fabric, and which one you choose depends entirely on which mods you want to run.
Forge is the older, more established mod loader with the biggest library of mods. Fabric is newer, lighter, and updates faster when new Minecraft versions release. Check your mod’s download page—it’ll tell you which loader it requires. Some mods work with both, but most are built for one or the other.
You’ll also need server hosting that gives you file access and enough RAM. Most modpacks need at least 4GB of RAM to run smoothly, and larger packs like All the Mods can demand 8GB or more. GameTeam.io offers modded Minecraft hosting starting at $1/GB with 20% off for new customers—and you get full FTP access for installing whatever mods you want.
Installing the Mod Loader on Your Server
First, make sure your server is stopped. Installing or changing mod loaders while the server is running will corrupt files.
For Forge Servers
Download the Forge installer from the official Forge website, making sure the version matches your Minecraft version exactly. Run the installer and select “Install Server.” Point it to your server directory, and it’ll create the necessary files.
You’ll see a new file called forge-[version].jar. This replaces your standard server.jar file. Update your startup script to launch this file instead of the vanilla server jar.
For Fabric Servers
Fabric’s installation is simpler. Download the Fabric server launcher from fabricmc.net, select your Minecraft version, and run the installer. It creates a fabric-server-launch.jar file that you’ll use to start your server.
Fabric also requires the Fabric API mod installed in your mods folder—it’s essentially a library that most Fabric mods depend on. Download it from CurseForge or Modrinth and drop it in the mods folder like any other mod.
Adding Mods to Your Minecraft Server
Once your mod loader is installed and working, adding mods is straightforward. Download the mod files (they’re .jar files) and place them in the mods folder in your server directory. If the folder doesn’t exist, create it.
Critical point: Every player connecting to your server needs the exact same client-side mods installed. Server-side mods (like performance optimizers or world generation mods) only need to be on the server, but gameplay mods need to be on both the server and every client.
Creating a Mod List for Players
Make it easy for your players. Create a simple text document listing every mod they need, with download links and version numbers. Better yet, create a custom modpack using CurseForge or create a server files download that includes all the mods pre-configured.
Version mismatches cause 90% of connection problems. If your server runs “JourneyMap 5.9.7” and a player has “JourneyMap 5.9.8,” they won’t be able to join. Document everything.
Configuring Mods and Server Settings
Most mods create config files in the config folder after the server runs for the first time. These files control how mods behave—spawn rates, recipe changes, performance settings, and more.
Start your server once with the mods installed, then stop it. Check the config folder and review the settings. Some mods have aggressive default settings that can lag servers or break game balance. Understanding the difference between plugins and mods helps you optimize performance better.
Memory Allocation
Modded servers need more RAM than vanilla. Edit your startup script to allocate appropriate memory:
- Small modpacks (10-30 mods): 4GB minimum
- Medium modpacks (30-80 mods): 6-8GB
- Large modpacks (80+ mods): 8-12GB or more
Use the -Xms and -Xmx flags in your Java arguments. For example: -Xms4G -Xmx6G sets minimum 4GB and maximum 6GB.
Testing Your Modded Server
Before inviting players, test everything yourself. Install the same mods in your Minecraft client and connect to the server. Check that:
- All mods load without errors in the server console
- You can connect without version mismatch errors
- Mod features work correctly in-game
- Server performance is acceptable (check TPS with
/forge tpsor Fabric alternatives) - World generation works if you’re using biome or dimension mods
The server console will show errors if mods conflict or if dependencies are missing. Read error messages carefully—they usually tell you exactly what’s wrong.
Common Problems and How to Fix Them
Server Won’t Start After Adding Mods
Check the crash log in the crash-reports folder. Usually this means a mod requires a dependency you didn’t install, or two mods are incompatible. Remove mods one at a time to identify the problem.
Players Can’t Connect
Version mismatches are the usual culprit. Verify that players have the exact same mod versions as the server. Also check that they’re using the correct mod loader version—Forge 1.19.2 and 1.19.3 aren’t interchangeable.
Server Lag with Mods Installed
Some mods are performance killers. Add performance optimization mods like Sodium (Fabric) or Magnesium (Forge). Reduce view distance in server.properties. Check which mods are causing tick lag using profiling tools like Spark.
If you’re running complex modpacks, consider specialized hosting for demanding modpacks that provides better hardware allocation.
Mod Features Don’t Work
Some features require both server and client installation. Others need specific permissions or config changes. Read the mod’s documentation—most popular mods have wikis or detailed CurseForge pages explaining setup requirements.
Updating Mods on Your Server
Mod updates can add features, fix bugs, or break everything. Never update mods on a live server without testing first.
Create a backup of your entire server folder before updating anything. Download the new mod version, replace the old .jar file in the mods folder, and test on a separate instance if possible. Check the mod’s changelog for breaking changes or new dependencies.
When you update server mods, all players need to update their client mods too. Announce updates in advance and provide clear instructions.
Using Modpacks Instead of Individual Mods
Modpacks bundle dozens or hundreds of mods that are pre-configured to work together. They’re easier than assembling your own mod collection, especially for beginners.
Popular modpacks like All the Mods, RLCraft, or Create: Above and Beyond have dedicated server files you can download. These include all the mods, configs, and scripts already set up. Setting up modpack servers like Create Stellar becomes much simpler with pre-configured files.
Many hosting providers offer one-click modpack installation, which handles all the technical setup automatically. This eliminates most compatibility issues and gets you running faster.
Frequently Asked Questions
Can I use Forge and Fabric mods together?
No. Forge and Fabric are separate mod loaders that don’t work together. You must choose one or the other. There are hybrid loaders in development, but they’re experimental and not recommended for stable servers.
Do all players need to install mods?
It depends on the mod. Client-side mods that only affect visuals or HUD elements don’t need to be on the server. Server-side mods that only affect server mechanics don’t need to be on clients. But most gameplay mods need to be installed on both the server and all clients.
How many mods can a server handle?
There’s no hard limit—it depends on your server’s hardware and the mods themselves. Some lightweight mods barely impact performance, while a single poorly-optimized mod can destroy server TPS. Most servers handle 50-100 well-optimized mods without issues if they have adequate RAM and CPU power.
Can I add mods to an existing world?
Sometimes. Mods that only add items or mechanics usually work fine. Mods that change world generation or add new biomes can cause chunk errors at the borders between old and new terrain. Always backup your world before adding mods to an existing save.
Why does my modded server use so much RAM?
Mods add content, features, and complexity that require more memory. World generation mods, large content packs, and mods with complex systems all increase RAM usage. This is normal—just make sure you’ve allocated enough memory in your server startup parameters.
Final Tips for Running a Modded Server
Keep your mod list focused. More isn’t always better—a carefully chosen set of 30 mods that work well together beats 200 random mods that conflict and lag. Read mod descriptions carefully and check compatibility before installing anything.
Document your setup. Keep a list of every mod, version number, and config change. When something breaks (and it will), you’ll need this information to troubleshoot. Regular backups are non-negotiable with modded servers—corruption happens, and you don’t want to lose weeks of player progress.
Join the communities around your favorite mods. Discord servers and subreddits for popular mods are goldmines of troubleshooting help and optimization tips. Other server admins have probably solved the exact problem you’re facing.
