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How to install mods

Updated July 02, 2026
Minecraft
Minecraft Java: Mods and Modpacks | GameServerKings KB

Minecraft Java: Mods and Modpacks

Mods change the game itself: new blocks, mobs, dimensions, machines, and mechanics. Unlike plugins, mods require every player to install the same mod loader and mods on their client. This guide covers Forge, Fabric, NeoForge, and the easiest path of all: installing a community modpack.

Mods only work on Forge/Fabric/NeoForge server types. For Paper/Spigot servers, you want Plugins instead. Set your server type in the Startup tab as covered in Getting Started.

Mods vs Plugins

PluginsMods
Server typePaper, Spigot, PurpurForge, Fabric, NeoForge
Client install neededNoYes (same loader + mods)
Changes base gameNo (server-side behavior only)Yes (new content)
Folderplugins/mods/

If you want new content (machines, dimensions, creatures), you need mods. If you want server management and quality-of-life without client installs, you want plugins.

Forge

  1. Set the Startup type to forge.
  2. Choose the Minecraft and Forge versions.
  3. Drop mod .jar files into the mods/ folder.
  4. Restart.

Fabric

  1. Set the Startup type to fabric.
  2. Drop mods (.jar) into mods/.
  3. Many Fabric mods need Fabric API; download it from Modrinth and place it in mods/ alongside your other mods.
  4. Restart.

NeoForge

NeoForge is a newer fork of Forge with broad mod compatibility for recent Minecraft versions.

  1. Set the Startup type to neoforge.
  2. Choose the Minecraft and NeoForge versions.
  3. Drop mods into mods/.
  4. Restart.

Client Requirements

For any modded server, players need:

  • The same mod loader installed via the Minecraft launcher (Forge/Fabric/NeoForge)
  • The same mods in their local mods/ folder
  • Usually the same Minecraft version

Document your exact mod list and loader version, and link it in your server description. Mismatched mods are the number one reason players cannot connect to a modded server.

The simplest mod approach is to install a modpack built and tested by a community team. Players install the same pack with one click through a launcher like CurseForge or Modrinth or Prism.

Big sources:

Installing a Modpack

We can install many popular packs through the Modpack variable in the Startup tab; check the egg's documentation first, since that is the easiest route.

Otherwise, install manually:

  1. Download the pack's Server Files archive (most packs publish one separately from the client pack).
  2. Upload it to the server, replacing the default mods/, config/, and any startup scripts as the pack's instructions specify.
  3. Set the matching Minecraft and loader version in the Startup tab.
  4. Restart.

Notable Packs

  • All The Mods 9 (ATM9): A kitchen-sink pack with hundreds of mods
  • FTB Skies: A modern skyblock pack
  • Better Minecraft: Vanilla-plus exploration and adventure
  • Create: Above and Beyond: Built around the Create automation mod
  • Vault Hunters: Roguelike progression
  • Cobblemon: Pokemon-style creature collecting

Memory for Modded Servers

Modded servers are far more memory-hungry than vanilla or plugin servers, so lean toward the high end of your plan's heap. See Memory Allocation for the Xmx guidance. If the server crashes with an out-of-memory error, raise the Xmx value in the Startup tab.

Common Issues

  • Players cannot connect to a modded server: Mod mismatch. Players need the exact same loader version and mod list. Share a pack link rather than a loose mod list.
  • Server crashes on boot with a mod error: The console names the offending mod and usually the reason (missing dependency, wrong MC version). Remove or update that mod.
  • Out of memory: Raise the JVM heap (Xmx) in the Startup tab. Modded servers are memory-hungry.
  • Pack runs locally but not on the server: You installed the client pack instead of the server files. Download the pack's separate Server Files archive.
  • Mod works alone but conflicts in a pack: Two mods touch the same game system. Check the pack's known-incompatibilities list or the crash log for the conflicting pair.
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