Getting Started

RemapIDs is configured entirely through JSON files in your config folder. This page takes you from a fresh install to a working remap.

Requirements

Minecraft	Loader	Java
1.20.1	Forge	17
1.20.1	Fabric	17
1.21.1	NeoForge	21
1.21.1	Fabric	21

There are no other dependencies. Fabric API is not needed.

Installation

Drop the jar for your loader and Minecraft version into your mods/ folder. For multiplayer, install it on the server and on every client: remaps change registry IDs on both sides, so a client without the mod would disagree with the server about what exists.

Back up first

Registry remaps rewrite what placed blocks and stored items resolve to. They are designed to be safe, but any tool that touches world data deserves a backup. Copy your world folder before adding remaps to an existing world.

Your first remap

Say your pack used to ship Ice and Fire, you removed it, and another mod provides a silver ingot. Without a remap, every stored iceandfire:silver_ingot vanishes the next time a chest loads. With one, it turns into the replacement.

1. Start the game once with the mod installed. It creates the config folder:

   • Directoryconfig

     • Directoryremapids

       • Directoryremaps/

         • …

2. Create a JSON file inside config/remapids/remaps/. The name is up to you; something descriptive like iceandfire_removal.json pays off once you have several.

   config/remapids/remaps/iceandfire_removal.json

   {
     "remaps": [
       {
         "source": "iceandfire:silver_ingot",
         "target": "othermod:silver_ingot",
         "types": ["item", "recipe", "loot_table", "tag"]
       }
     ]
   }

   Each entry says: wherever source appears, treat it as target. The types array limits which systems the remap touches. Leave it out to apply the remap to every type where the target exists.

3. Restart the game. Remaps are read during startup, and registry-level types (block, item, fluid, entity_type) only apply on a full restart. The reloadable types (recipe, loot_table, tag) can be refreshed later with /reload.

4. Verify it took effect. Hold any item and run:

   /remapids id hand

   If you hold the replacement silver ingot, the output includes the remap:

   Item: othermod:silver_ingot (Remapped from: iceandfire:silver_ingot)

Tip

/remapids id block does the same for the block you are looking at. Both commands work for any player, no op required. See Troubleshooting for the full command reference.

Where to go next

• Remap File Reference explains every field and remap type, plus wildcards and tags.
• Examples covers the common modpack scenarios end to end.