Simple Trading Device

Simple Trading Device adds portable trading items for Minecraft/NeoForge. A trading device stores a numeric trade value, accepts configured item or fluid inputs, and lets the player spend that stored value to buy configured outputs.

The mod ships with built-in vanilla Minecraft trading groups and also supports JSON-driven extension. You can:

• add entries to an existing built-in holder
• create a brand-new holder
• register a new trading device item that uses that holder

Main Features

• Portable trading devices with independent stored value.
• Built-in vanilla trading holders grouped by item theme.
• Item and fluid input conversion.
• Item and fluid output purchases.
• Durability-aware equipment pricing.
• JSON loading for extra trading entries.
• JSON loading for extra trading device items.
• Optional blank additional devices for custom holders.

How Trading Works

Right-click a trading device to open its UI.

• The center bar shows stored value.
• The left side shows accepted inputs.
• Insert an accepted item or fluid to convert it into stored value.
• The right side shows buyable outputs.
• Click an output entry to spend stored value and move the result into the output slot.

Purchase multiplier keys:

• No modifier: buy 1 unit
• Shift: buy 4 units
• Ctrl: buy 8 units
• Alt: buy 64 units

Items are priced and traded per single item. Fluids are priced and traded in 1000 mB units.

Configuration

The mod uses a YAML config file:

config/simple_trading_device/simple_trading_device.yaml

Default values:

general:
  enableTradingHolderJsonConfig: true
  enableTradingDeviceJsonConfig: false
  enableAdditionalTradingDevice: false

enableTradingHolderJsonConfig

Loads extra trading entries from:

config/simple_trading_device/trading_holder_entries.json

Default: true

enableTradingDeviceJsonConfig

Loads extra trading device items from:

config/simple_trading_device/trading_devices.json

Default: false

enableAdditionalTradingDevice

Registers ten extra blank devices:

• additional_trading_device_0
• additional_trading_device_1
• additional_trading_device_2
• additional_trading_device_3
• additional_trading_device_4
• additional_trading_device_5
• additional_trading_device_6
• additional_trading_device_7
• additional_trading_device_8
• additional_trading_device_9

These devices use holder keys additional_0 through additional_9.

Default: false

JSON Workflow

There are two JSON files:

• trading_holder_entries.json: defines trade contents
• trading_devices.json: defines extra trading device items

Use the following rules:

1. If you only want to add trades to an existing built-in device, edit trading_holder_entries.json.
2. If you want a completely new device, create a new holder in trading_holder_entries.json, then register a device for that holder in trading_devices.json.
3. JSON-registered devices also need a model file and language entry from your resource pack or generated assets.

Trading Holder Keys

Built-in holder keys:

Holder key	Device item	Content theme
common	simple_trading_device:common_trading_device	Dirt, stone, sand, gravel, clay, ice, obsidian, logs, planks, sticks
building	simple_trading_device:building_trading_device	Bricks, polished stone, glass, terracotta, concrete, wool
minerals	simple_trading_device:minerals_trading_device	Coal, copper, iron, gold, redstone, lapis, quartz, amethyst, diamond, emerald, netherite
farming	simple_trading_device:farming_trading_device	Seeds, crops, saplings, mushrooms, fruit, leather, feathers, honey
food	simple_trading_device:food_trading_device	Bread, fish, meat, stew, golden food
mob_drops	simple_trading_device:mob_drops_trading_device	Rotten flesh, bones, string, gunpowder, slime, blaze drops, ender pearls, ghast tears
redstone	simple_trading_device:redstone_trading_device	Redstone dust, switches, rails, repeaters, comparators, pistons, hoppers, TNT
utility	simple_trading_device:utility_trading_device	Torches, containers, workstations, buckets, minecarts, compass, clock, anvil, enchanting table, boats
equipment	simple_trading_device:equipment_trading_device	Tools, weapons, armor, bows, shield, fishing rod, shears, trident, horse armor
nether	simple_trading_device:nether_trading_device	Nether blocks, Nether wood, Nether wart, glowstone, lava, blaze rods, ancient debris
end	simple_trading_device:end_trading_device	End stone, purpur, chorus items, eyes of ender, dragon breath, shulker shells, elytra
treasure	simple_trading_device:treasure_trading_device	Saddle, nautilus shell, heart of the sea, conduit, totem, nether star, beacon, music discs, smithing templates
additional_0 to additional_9	Optional additional devices	Empty holders intended for JSON content

You may also create a completely new holder key in JSON. A new holder only becomes visible in-game when some trading device uses that same holder key.

trading_holder_entries.json

Path:

config/simple_trading_device/trading_holder_entries.json

This file must be a JSON array.

Each object must contain a holder field. After that, you can use either:

• a single direct entry on the same object
• an entries array

Supported Fields

Field	Required	Description
holder	Yes	Holder key such as mob_drops, nether, additional_0, or a custom key
entries	No	Array of entry objects
type	Yes for each entry	Must be input, output, or both
item	Item entry only	Vanilla ItemStack JSON parsed by the Minecraft codec
fluid	Fluid entry only	NeoForge FluidStack JSON parsed by the NeoForge codec
yield	Yes	Trade value
baseYield	Optional alternative to yield	Same meaning as yield
tooltip	No	Single tooltip line
tooltips	No	Array of tooltip lines

Rules:

• type only accepts input, output, or both
• exactly one of item or fluid must exist
• yield must be greater than 0
• item ids and fluid ids should use full names such as minecraft:diamond
• for item stacks, count is optional and defaults to the vanilla codec result
• for fluid stacks, amount is optional and the mod fills in 1000
• invalid entries are logged and skipped

Quantity And Component Notes

• JSON item inputs are matched by Item and priced per single item. item.count is parsed by the codec, but it does not change input matching or the per-unit value calculation.
• JSON fluid inputs are matched by Fluid and priced per 1000 mB. fluid.amount is parsed by the codec, but input matching and per-unit value calculation still use the fluid type and a trade unit of 1000 mB.
• JSON item outputs buy 1 item per unit. Purchase modifiers therefore buy 1, 4, 8, or 64 items.
• JSON fluid outputs buy 1000 mB per unit. Purchase modifiers therefore buy 1000, 4000, 8000, or 64000 mB.
• JSON output entries preserve item or fluid components on the purchased resource, but output quantity still follows the fixed unit rules above.
• JSON input entries are not component-sensitive. If you need input matching or pricing that depends on full item or fluid components, register that trade in Java and provide a custom TradingHolder.YieldCalculator. See TradingHolderRegistry.registerItem(...), TradingHolderRegistry.registerFluid(...), and TradingHolder.YieldCalculator.

Type Meaning

• input: can be converted into stored value
• output: can be bought from stored value
• both: available as both input and output

Minimal Single Entry Example

[
  {
    "holder": "mob_drops",
    "type": "output",
    "item": {
      "id": "minecraft:creeper_spawn_egg"
    },
    "yield": 2048
  }
]

Holder Block Example

[
  {
    "holder": "spawn_eggs",
    "entries": [
      {
        "type": "input",
        "item": {
          "id": "minecraft:rotten_flesh"
        },
        "yield": 8,
        "tooltip": "Input currency for spawn egg trades"
      },
      {
        "type": "input",
        "item": {
          "id": "minecraft:bone"
        },
        "yield": 12
      },
      {
        "type": "output",
        "item": {
          "id": "minecraft:zombie_spawn_egg"
        },
        "yield": 2048
      },
      {
        "type": "output",
        "item": {
          "id": "minecraft:skeleton_spawn_egg"
        },
        "yield": 2048
      },
      {
        "type": "output",
        "item": {
          "id": "minecraft:creeper_spawn_egg"
        },
        "yield": 4096
      }
    ]
  }
]

Fluid Example

[
  {
    "holder": "fluid_supplies",
    "entries": [
      {
        "type": "both",
        "fluid": {
          "id": "minecraft:water"
        },
        "yield": 16,
        "tooltip": "1000 mB per trade unit"
      },
      {
        "type": "both",
        "fluid": {
          "id": "minecraft:lava"
        },
        "yield": 64
      }
    ]
  }
]

trading_devices.json

Path:

config/simple_trading_device/trading_devices.json

This file is only loaded when enableTradingDeviceJsonConfig is true.

The file must be a JSON array. Each object registers one extra trading device item.

Supported Fields

Field	Required	Description
id	Yes	Item id path only, for example spawn_egg_trading_device
holder	Yes	Holder key used by the device
maxStorage	Yes	Maximum stored trade value

Rules:

• id must not include a namespace
• holder may point to a built-in holder or a new custom holder
• maxStorage must be greater than 0

Example:

[
  {
    "id": "spawn_egg_trading_device",
    "holder": "spawn_eggs",
    "maxStorage": 5000000
  },
  {
    "id": "fluid_supplies_trading_device",
    "holder": "fluid_supplies",
    "maxStorage": 1000000
  }
]

Assets Required For JSON Devices

JSON device registration creates the item and binds it to a holder. It does not automatically give you final distributed client assets.

For every JSON device id, also provide:

• assets/simple_trading_device/models/item/<id>.json
• assets/simple_trading_device/lang/en_us.json
• optionally assets/simple_trading_device/lang/zh_cn.json

Model Example

If your device id is spawn_egg_trading_device, create:

assets/simple_trading_device/models/item/spawn_egg_trading_device.json

Example model:

{
  "parent": "simple_trading_device:item/trading_device",
  "textures": {
    "layer0": "simple_trading_device:item/trading_device_shell",
    "layer1": "minecraft:item/zombie_spawn_egg"
  }
}

The shared parent model is:

assets/simple_trading_device/models/item/trading_device.json

It renders the shell as the base layer and a centered 8x8 overlay as the top layer.

Language Example

Add a translation entry:

{
  "item.simple_trading_device.spawn_egg_trading_device": "Spawn Egg Trading Device"
}

Without a model or language entry, the device can still register, but it will not have the intended client presentation.

Full Example: Create A New Custom Device

1. Enable JSON device loading:

general:
  enableTradingHolderJsonConfig: true
  enableTradingDeviceJsonConfig: true

1. Register a holder and its trade contents in trading_holder_entries.json:

[
  {
    "holder": "spawn_eggs",
    "entries": [
      {
        "type": "input",
        "item": {
          "id": "minecraft:bone"
        },
        "yield": 12
      },
      {
        "type": "output",
        "item": {
          "id": "minecraft:zombie_spawn_egg"
        },
        "yield": 2048
      }
    ]
  }
]

1. Register the device in trading_devices.json:

[
  {
    "id": "spawn_egg_trading_device",
    "holder": "spawn_eggs",
    "maxStorage": 5000000
  }
]

1. Add the model file:

{
  "parent": "simple_trading_device:item/trading_device",
  "textures": {
    "layer0": "simple_trading_device:item/trading_device_shell",
    "layer1": "minecraft:item/zombie_spawn_egg"
  }
}

1. Add the language entry:

{
  "item.simple_trading_device.spawn_egg_trading_device": "Spawn Egg Trading Device"
}

After that, the device should appear in the trading devices creative tab and open the holder you defined.

Built-in Device Storage

Device	Max storage
Common Trading Device	100,000
Building Trading Device	150,000
Minerals Trading Device	2,000,000
Farming Trading Device	100,000
Food Trading Device	100,000
Mob Drops Trading Device	250,000
Redstone Trading Device	500,000
Utility Trading Device	500,000
Equipment Trading Device	5,000,000
Nether Trading Device	2,000,000
End Trading Device	5,000,000
Treasure Trading Device	10,000,000
Additional Trading Devices	100,000,000
JSON Trading Devices	Defined by maxStorage

Development

Source repository:

• Repository: https://github.com/wanggugu197/Simple-Trading-Device
• Issues: https://github.com/wanggugu197/Simple-Trading-Device/issues

Environment requirements:

• Java 25
• Gradle 9.x
• Minecraft 26.1.2
• NeoForge 26.1.2.71+

License

GNU Lesser General Public License v3.