How to Install Minecraft Mods with Forge or Fabric

Forge / Fabric

Mods vs Plugins

A Minecraft mod changes the game code through a loader such as Forge or Fabric. A plugin runs on a plugin server such as Paper or Purpur and usually does not require players to install anything. Mods are more powerful for client visuals, mobs, blocks, items and deep gameplay changes, but they need stricter version matching.

Before installing a mod, read whether it is client-only, server-only, or required on both sides. Installing the wrong side can cause crashes, missing registries, or players being unable to join.

Install Steps

1. Check if the mod needs Forge or Fabric. Do not mix loaders unless the mod explicitly supports both.
2. Install the correct loader. Use the same loader family and Minecraft version that the mod was built for.
3. Match the Minecraft version. A mod built for 1.20.1 usually will not work on 1.21.3.
4. Put the .jar file inside the mods folder. On a client this is normally `.minecraft/mods`.
5. Start Minecraft and check the Mods menu. Confirm the mod is detected before joining a world or server.
6. For servers, install the mod on both server/client if required. Content mods often need both; small client utilities may only need the client.

Common Mod Install Problems

• The wrong loader was used, such as Forge instead of Fabric.
• The Minecraft version does not match the mod build.
• A required dependency is missing.
• A client-only mod was installed on the server.
• A server-side content mod is missing from the client.