Configuration Reference

Complete reference for RemapIDs configuration. All configuration is done through JSON files placed in config/remapids/remaps/.

JSON Validation

If your remaps aren't taking effect, check for JSON syntax errors. A misplaced comma or missing bracket will cause the file to fail silently. Use a JSON validator to verify your files.

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File Structure

• Remap configs: config/remapids/remaps/*.json — all .json files are loaded automatically in alphabetical order
• Custom numerical IDs: config/remapids/numerical_ids.json — optional file for modded pre-1.13 numerical ID mappings (see Numerical IDs Guide)
• Each remap file is independent — organize however you like (e.g., one file per removed mod, one file per remap type)

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remaps

The top-level remaps array contains all remap entries for the file.

Type: Array of remap objects

{
  "remaps": [
    {
      "source": "oldmod:copper_ingot",
      "target": "minecraft:copper_ingot",
      "types": ["item", "block"]
    },
    {
      "source": "oldmod:copper_ore",
      "target": "minecraft:copper_ore"
    }
  ]
}

---

remaps[].source

The original ID to redirect.

Type: String (namespaced ID or numerical ID)

• Namespaced ID: namespace:path format (e.g., "oldmod:silver_ingot")
• Numerical ID: Pre-1.13 numerical block/item ID, optionally with metadata (e.g., "1", "35:14") — see Numerical IDs Guide
• Supports * wildcard for pattern matching (see Wildcards Guide)
• Prefix with # for tag remaps (e.g., "#forge:ingots/gold") — see Tag Remapping Guide

{
  "source": "oldmod:silver_ingot",
  "target": "newmod:silver_ingot"
}

Numerical ID example

{
  "source": "35:14",
  "target": "somemod:red_block",
  "types": ["block"]
}

The numerical ID 35:14 (red wool in pre-1.13) is automatically resolved to minecraft:red_wool before processing. See the Numerical IDs Guide for details.

---

remaps[].target

The destination namespaced ID that the source will be redirected to.

Type: String (namespaced ID)

• Same format requirements as source
• If source uses *, target must also use * (and vice versa)
• For registry types, the target must exist in the game's registries — a warning is logged if it's not found at validation time, but injection is still attempted (modded targets may not be registered yet during early validation)

{
  "source": "oldmod:*",
  "target": "newmod:*"
}

---

remaps[].types

Optionally filter which remap types this entry applies to.

Type: String array (optional) Default: [] (empty = applies to all 7 types)

Value	Category	Requires Restart	Description
block	Registry	Yes	Block registry IDs
item	Registry	Yes	Item registry IDs
fluid	Registry	Yes	Fluid registry IDs
entity_type	Registry	Yes	Entity type registry IDs
tag	Reloadable	No	Tag definitions
recipe	Reloadable	No	Recipe IDs and ingredient/result references
loot_table	Reloadable	No	Loot table ID lookups and item references

Filtered example

Only remap items and blocks — leave tags, recipes, and loot tables unchanged:

{
  "source": "oldmod:silver_ingot",
  "target": "newmod:silver_ingot",
  "types": ["item", "block"]
}

Unfiltered example

Apply to all remap types (block, item, fluid, entity_type, tag, recipe, loot_table):

{
  "source": "oldmod:silver_ingot",
  "target": "newmod:silver_ingot"
}

---

Processing Pipeline

When the game loads, RemapIDs processes config files in this order:

1. Parse — All .json files in the remaps directory are loaded alphabetically
2. Resolve numerical IDs — Pre-1.13 numerical sources (e.g., "35:14") are converted to post-flattening string IDs (e.g., "minecraft:red_wool")
3. Expand wildcards — * patterns are matched against known registry IDs
4. Group by type — Entries are organized by their applicable remap types
5. Flatten chains — Transitive mappings are resolved (A→B + B→C = A→C, max depth 10)
6. Warn — Registry type targets are checked against known IDs. Missing targets produce a warning but are not removed — modded targets may not be registered yet at this point
7. Apply — The final remap configuration is activated. On Forge, alias injection happens via FMLLoadCompleteEvent to ensure all modded content is available. Block state IDs are remapped in Block.BLOCK_STATE_REGISTRY for consistent network serialization

---

Example Config Files

Mod migration

{
  "remaps": [
    {
      "source": "iceandfire:silver_ingot",
      "target": "thermal:silver_ingot",
      "types": ["item"]
    },
    {
      "source": "iceandfire:silver_block",
      "target": "thermal:silver_block",
      "types": ["block", "item"]
    },
    {
      "source": "iceandfire:silver_ore",
      "target": "thermal:silver_ore",
      "types": ["block", "item"]
    }
  ]
}

Replace vanilla with modded

{
  "remaps": [
    {
      "source": "minecraft:copper_block",
      "target": "create:brass_block",
      "types": ["item", "block"]
    },
    {
      "source": "minecraft:copper_ingot",
      "target": "create:brass_ingot",
      "types": ["item"]
    }
  ]
}

Tag consolidation

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