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Examples

Real-world modpack scenarios showing how to use RemapIDs to solve common problems.

1. Replace a Removed Mod's Items​

Scenario: You removed Ice and Fire from your modpack, but players have silver ingots in their inventories and chests.

Solution: Remap the specific items to their replacements:

{
  "remaps": [
    {
      "source": "iceandfire:silver_ingot",
      "target": "thermal:silver_ingot",
      "types": ["item"]
    },
    {
      "source": "iceandfire:silver_nugget",
      "target": "thermal:silver_nugget",
      "types": ["item"]
    }
  ]
}
tip

For registry remaps like items, the target mod must be loaded. Make sure the replacement mod is installed.

2. Wildcard Migration Between Mods​

Scenario: You're replacing an entire mod and both mods use the same naming convention for their items.

Solution: Use wildcards to remap all matching IDs at once:

{
  "remaps": [
    {
      "source": "iceandfire:silver_*",
      "target": "thermal:silver_*",
      "types": ["item", "block"]
    }
  ]
}

This automatically expands to cover silver_ingot, silver_nugget, silver_block, silver_ore, and any other silver_* IDs from Ice and Fire.

warning

Wildcards only match IDs that exist in the current game registries. If the source mod has already been removed, use explicit source/target pairs instead.

3. Redirect Recipe Ingredients​

Scenario: A removed mod added a custom tag that other mods' recipes reference. Those recipes now break because the tag is empty.

Solution: Use a tag-to-item remap to substitute a specific item:

{
  "remaps": [
    {
      "source": "#removedmod:special_gems",
      "target": "minecraft:emerald",
      "types": ["recipe"]
    }
  ]
}

Every recipe that used {"tag": "removedmod:special_gems"} as an ingredient will now use {"item": "minecraft:emerald"}.

4. Consolidate Tags After Mod Removal​

Scenario: A removed mod registered items under its own tag namespace. Other mods check these tags and find them empty.

Solution: Merge the old tags into standard tags:

{
  "remaps": [
    {
      "source": "#removedmod:ingots/silver",
      "target": "#forge:ingots/silver",
      "types": ["tag"]
    },
    {
      "source": "#removedmod:ores/silver",
      "target": "#forge:ores/silver",
      "types": ["tag"]
    }
  ]
}

Items that were tagged under the removed mod's namespace are now included in the standard Forge tags.

5. Remap Entity Types for World Migration​

Scenario: A mod updated and changed its entity type IDs between versions. Existing worlds have entities saved under the old IDs.

Solution: Remap the old entity type IDs to the new ones:

{
  "remaps": [
    {
      "source": "examplemod:old_goblin",
      "target": "examplemod:goblin",
      "types": ["entity_type"]
    },
    {
      "source": "examplemod:old_dragon",
      "target": "examplemod:fire_dragon",
      "types": ["entity_type"]
    }
  ]
}

6. Multi-File Organization​

Scenario: Your modpack has several mod replacements and you want to keep remaps organized.

Solution: Split remaps across multiple files. RemapIDs processes them alphabetically and chain flattening works across files.

File: 01-removed-mods.json

{
  "remaps": [
    {
      "source": "oldcoppermod:copper_ingot",
      "target": "minecraft:copper_ingot",
      "types": ["item", "block"]
    },
    {
      "source": "oldsilvermod:silver_ingot",
      "target": "thermal:silver_ingot",
      "types": ["item"]
    }
  ]
}

File: 02-tag-consolidation.json

{
  "remaps": [
    {
      "source": "#oldcoppermod:ingots/copper",
      "target": "#forge:ingots/copper",
      "types": ["tag"]
    }
  ]
}

File: 03-recipe-fixes.json

{
  "remaps": [
    {
      "source": "#oldsilvermod:dusts/silver",
      "target": "thermal:silver_dust",
      "types": ["recipe"]
    }
  ]
}
tip

Prefix filenames with numbers (e.g., 01-, 02-) to control processing order explicitly, since files are loaded alphabetically.

7. Full Modpack Migration Config​

A comprehensive config for a modpack that removed two mods and replaced them with alternatives:

{
  "remaps": [
    {
      "source": "iceandfire:silver_ingot",
      "target": "thermal:silver_ingot",
      "types": ["item"]
    },
    {
      "source": "iceandfire:silver_block",
      "target": "thermal:silver_block",
      "types": ["item", "block"]
    },
    {
      "source": "iceandfire:silver_ore",
      "target": "thermal:silver_ore",
      "types": ["item", "block"]
    },
    {
      "source": "iceandfire:silver_nugget",
      "target": "thermal:silver_nugget",
      "types": ["item"]
    },
    {
      "source": "#iceandfire:ingots/silver",
      "target": "#forge:ingots/silver",
      "types": ["tag"]
    },
    {
      "source": "#iceandfire:ores/silver",
      "target": "#forge:ores/silver",
      "types": ["tag"]
    },
    {
      "source": "oldtech:copper_wire",
      "target": "immersiveengineering:wire_copper",
      "types": ["item"]
    },
    {
      "source": "#oldtech:wires",
      "target": "immersiveengineering:wire_copper",
      "types": ["recipe"]
    }
  ]
}

Migration Workflow​

When migrating your modpack, follow this workflow:

  1. Identify which mods are being removed or replaced
  2. List the IDs that need remapping (items, blocks, entities, tags)
  3. Create a remap file in config/remapids/remaps/
  4. Add registry remaps (item, block) for items players may have in inventories or placed in the world
  5. Add tag remaps if other mods reference the removed mod's tags
  6. Add recipe remaps if recipe ingredients need redirecting
  7. Restart the game to apply registry remaps
  8. Check logs for [RemapIDs] messages — warnings indicate missing targets or invalid entries
  9. Test reloadable types with /reload to iterate quickly on tag, recipe, and loot table remaps

Next Steps​