How to install mods on a Minecraft server

Mods need a mod loader. A mod made for Fabric does not load on Forge, and a mod made for 1.21.1 does not load on 26.1, so the loader and the version come first. Pick the loader that the mods you want are made for; Fabric, Forge or NeoForge explains the difference.

1. Make a backup in the Backups tab.
2. Open Settings and go to Server software.
3. Choose Fabric, Forge or NeoForge as the server type and pick the Minecraft version your mods are made for.
4. Save and start the server once, so it creates the mods folder and its first files.

Paper, Purpur and Spigot run plugins, not mods. If you only want a few extras and players should join with a normal game, plugins may be the easier road: see install plugins.

1. Open the Mods tab of your server.
2. Under Verified Modrinth catalog, type the name of the mod in Search mods, for example lithium or farmer's delight.
3. The results are matched to your server type and Minecraft version, so a mod that does not fit your server does not show up.
4. Click Verify & install. The panel checks the file and puts it in /mods.
5. Restart the server to load it.

Every mod in the mods folder shows in the list above the catalog, with its file name and size. Filter installed mods finds one quickly when the list gets long.

For a mod that is not in the catalog, or a version you picked yourself:

1. On the mod's download page, pick the file for your loader and your exact Minecraft version. Mods are .jar files.
2. Stop the server.
3. In Files, open the mods folder and click Upload.
4. Choose the .jar file. Do not unpack it.
5. Start the server and watch the console while it loads.

Download mods only from the mod's own page on a known mod site. A .jar from a random link runs with full rights on your server.

Many mods need another mod to work, a library that holds shared code. The mod page lists these as dependencies. Without them the server stops at startup and the console names the mod that is missing.

• Fabric API is needed by almost every Fabric mod. Install it first on any Fabric server.
• Libraries such as Architectury, Cloth Config or GeckoLib come up often; install the version for the same loader and Minecraft version.
• A dependency marked optional adds extra features, but the mod starts without it.

Not every mod belongs in the same place. The mod page usually says where it runs.

A mod that only runs in the game, such as a shader loader, should stay off the server: at best it does nothing there, at worst the server refuses to start. Pre-generating the world with Chunky is covered in pre-generate your world.

When a content mod is missing or has another version in a player's game, the player cannot join and sees a list of what does not match. Two ways to keep everyone equal:

• Make a small modpack with the same mods and versions, and share it with your players. Their launcher installs it in one go.
• Keep a list of every mod with its exact version, and have players install the same files.

Join a modded server is the guide to send your players; it covers the launcher and the memory their game needs.

• Remove: click Remove next to the mod in the Mods tab and restart. The panel says "Mod removed. Restart to apply."
• Update: remove the old file and install the new one. Two versions of the same mod in mods stop the server from starting.
• Make a backup first. Removing a content mod also removes its blocks and items from the world, and that cannot be undone without the backup.
• Update the same mods in your players' games at the same time, or they cannot join.

Every mod takes some memory. A handful of light mods runs well on the RAM of a normal server; a large collection of content mods needs about as much as a heavy modpack, 12 to 16 GB. How much RAM for a Minecraft server has the full table, and reduce lag helps when a modded server feels slow.