Generating Minecraft mods with Forge and Fabric

A Bukkit-family plugin runs on the server only, and vanilla clients can join without installing anything. A mod modifies the game itself, which means it can add real blocks, items, entities and rendering - and usually has to be installed on the client as well as the server.

If your idea needs new blocks or items that players see in their inventory, you need a mod. If it is about server behaviour, commands or rules, a plugin is simpler and reaches more players.

Codexe scaffolds a complete Gradle project for Forge and NeoForge: build script, mod descriptor, registry classes and the entry point with its event bus subscriptions.

src/main/
├── java/com/example/mymod/
│   ├── MyMod.java              // @Mod entry point
│   ├── init/ModItems.java      // DeferredRegister<Item>
│   └── init/ModBlocks.java
└── resources/
    ├── META-INF/mods.toml
    └── assets/mymod/...

mods.toml is Forge’s descriptor. It declares the mod id, the loader version range and dependency constraints:

modLoader="javafml"
loaderVersion="[47,)"
license="MIT"

[[mods]]
modId="mymod"
version="1.0.0"
displayName="My Mod"

[[dependencies.mymod]]
    modId="minecraft"
    mandatory=true
    versionRange="[1.20.1,1.21)"
    ordering="NONE"
    side="BOTH"

The modId must be lowercase and must match the id used in code and in the asset paths. Registration goes through DeferredRegister rather than direct registry writes, because Forge controls when registries are open.

Fabric projects use the Loom Gradle plugin and a JSON descriptor. The loader is lighter than Forge and tends to update to new Minecraft versions sooner.

{
  "schemaVersion": 1,
  "id": "mymod",
  "version": "1.0.0",
  "name": "My Mod",
  "environment": "*",
  "entrypoints": {
    "main": ["com.example.mymod.MyMod"]
  },
  "mixins": ["mymod.mixins.json"],
  "depends": {
    "fabricloader": ">=0.15.0",
    "minecraft": "~1.20.1"
  }
}

The entrypoints block is what Fabric calls on load, and it is split by environment - main, client and server. Putting client-only rendering code in main is a common way to crash a dedicated server.

Mixins

Fabric has no large built-in event bus, so mods change vanilla behaviour by injecting into game classes with Mixin. Codexe generates the mixin JSON and the mixin classes alongside the mod when your request needs them.

Use the Forge mod generator or the Fabric mod generator.