Installing Custom Advancements on Fabric or NeoForge

Step-by-step instructions to install Custom Advancements on Fabric and NeoForge for Minecraft 1.21.1, including all required dependencies.

Installing Custom Advancements takes only a few minutes. The process differs slightly between Fabric and NeoForge, mainly because the Fabric build requires two additional library mods. Follow the tab for your loader below, then launch the game — the mod will create its working folder automatically on first run.

You can download Custom Advancements from either of the two official distribution platforms:

• CurseForge: https://www.curseforge.com/minecraft/mc-mods/custom-advancements
• Modrinth: https://modrinth.com/mod/custom-advancements

Installation Steps

Fabric

Forge Config API Port is required. Custom Advancements uses NeoForge’s configuration API on the Fabric loader via the Forge Config API Port compatibility library. The mod will not load without it — you will see a missing-dependency error on the title screen if it is absent.

1. Install a compatible Fabric Loader

   Download and install Fabric Loader 0.18.6 or newer from https://fabricmc.net/use/installer/ for Minecraft 1.21.1. Select the correct Minecraft version in the installer before confirming.

2. Add Fabric API

   Download the latest Fabric API build for Minecraft 1.21.1 from CurseForge or Modrinth and place the .jar file in your mods/ folder.

3. Add Forge Config API Port

   Download Forge Config API Port version 21.1.6 or newer (the version built for Minecraft 1.21.1 / Fabric) from Modrinth and place the .jar file in your mods/ folder.

4. Add Custom Advancements

   Download the Fabric build of Custom Advancements for Minecraft 1.21.1 from CurseForge or Modrinth and place the .jar file in your mods/ folder.

5. Launch the game

   Start Minecraft using your Fabric profile. On first launch, the mod creates the customadvancements/ folder inside your game directory. You are now ready to add custom advancements.

NeoForge

1. Install a compatible NeoForge version

   Download and install NeoForge 21.1.47 or newer from https://neoforged.net for Minecraft 1.21.1. NeoForge ships its own configuration API, so no extra dependency mods are needed.

2. Add Custom Advancements

   Download the NeoForge build of Custom Advancements for Minecraft 1.21.1 from CurseForge or Modrinth and place the .jar file in your mods/ folder.

3. Launch the game

   Start Minecraft using your NeoForge profile. On first launch, the mod creates the customadvancements/ folder inside your game directory. You are now ready to add custom advancements.

The customadvancements/ Folder

After the first successful launch, your game directory will contain a new folder called customadvancements/. This is where all of your custom advancement JSON files, language files, and textures live. The folder is created automatically — you do not need to create it manually.

The customadvancements/ folder behaves like a global datapack: its contents are injected into every world you play or host on that installation, not just a single world’s datapacks/ folder. This makes it ideal for modpack-wide advancement customization.

The expected layout inside the folder is:

customadvancements/
├── customadvancements/       ← advancement JSON files (namespace = "customadvancements")
│   └── my_tree/
│       ├── root.json
│       └── first_step.json
└── data/
    ├── lang/
    │   └── en_us.json        ← optional translation overrides
    └── textures/
        └── my_background.png ← optional custom background images

[INSERT IMAGE: The Custom Advancements mod entry shown in the Fabric/NeoForge mod list screen, confirming a successful install]