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Stacknator

Properly configurable stack sizes for any vanilla or modded items

Fabric
Loaders
Fabric
Downloads on Modrinth
2.4K
Followers on Modrinth
10
versions
8
Updated
June 21, 2026Jun 21
Published
in 2025

At a glance

Runs on Fabric
For Minecraft 1.21–26.3
Server only — players don't need to install it
Latest version — 2.0.1 from June 21, 2026
Requires Fabric API
License MIT — free
Where it's needed
In gamenot neededOn serverrequired

Install on the server only; players don't need it

Game versions1.21–26.3

Stacknator

Stacknator is a lightweight Minecraft mod for Fabric that lets you customize the maximum stack size of any vanilla or modded item via a simple configuration file. By modifying item data components during game initialization, Stacknator delivers a clean, efficient solution without performance overhead or hacky workarounds.

Compatibility

  • Required: Fabric API
  • Vanilla Items: Fully compatible.
  • Modded Items: Generally compatible with most mods.

Tags: Supported through the Filler feature.

Tip: To find an item's identifier, enable Advanced Tooltips in-game by pressing F3 + H, then hover over the item.

Installation

  1. Drop the Stacknator .jar into your mods folder.
  2. Start the server or load into a world.
  3. Edit the stacknator.json config file to set your desired stack sizes.
  4. Enjoy!

Required only on the server side for a survival gameplay, however it's recommended to have it on the client side as well to be fully compatible with some screens (e.g. creative screen).

Documentation

  • enabled:
    Enables or disables the mod.
    Type: boolean Default: true
  • log_modified_items:
    Toggles logging of successful stack size changes (other logs always show).
    Type: boolean Default: true
  • checks:
    Defines the checks to be performed.
    Type: object Default:

    • enable_checks:
      Enables or disables all checks.
      Type: boolean Default: true
    • check_damageable:
      Enables or disables the damageable check.
      Type: boolean Default: true
    • check_stackable:
      Enables or disables the stackable check.
      Type: boolean Default: false
    • check_minimum_stack_size:
      Enables or disables the minimum stack size check.
      Type: boolean Default: true
    • check_maximum_stack_size:
      Enables or disables the maximum stack size check.
      Type: boolean Default: true
  • remove_defaults:
    Removes all item entries that match the default stack size.
    Type: boolean Default: false
  • filler:
    Defines the filler settings.
    Type: object Default: {}

    • enable_filler:
      Enables or disables the filler. When enabled, the mod will iterate all registered items and apply the filler rules to each item while enforcing the configured checks.
      Type: boolean Default: false
    • reset_stacks:
      Enables or disables resetting of stack sizes to the default values, overriding any defined custom stack size.
      Type: boolean Default: false
    • run_once:
      Disables the filler after one run.
      Type: boolean Default: true
    • tag_priority:
      Enables or disables prioritizing tags over item entries when applying the filler.
      Type: boolean Default: true
    • tags:
      Defines tag identifiers and their custom stack sizes.
      Type: object Default: {}
  • sort_items:
    Enables or disabled sorting the item entries alphabetically by their keys.
    Type: boolean Default: true
  • items:
    Defines item identifiers and their custom stack sizes.
    Type: object Default: {}

Checks

Stacknator performs the following checks for each item/tag entry in the config file:

  • Entry Key Format:
    Verifies if the entry key follows the namespace:item format.
    On Failure: Skips the entry.
  • Item Damageable:
    Ensures the item is not damageable (e.g. tools, weapons and armor).
    On Failure: Skips the entry.
  • Item Stackable:
    Confirms the item is stackable (default maximum stack above 1).
    On Failure: Skips the entry.
  • Entry Value Below 1:
    Checks if the stack size is less than 1.
    On Failure: Skips the entry.
  • Entry Value Above 99:
    Checks if the stack size exceeds 99.
    On Failure: Adjusts to 99.

Full Configuration Example

{
  "enabled": true,
  "log_modified_items": true,
  "checks": {
    "enable_checks": true,
    "check_damageable": true,
    "check_stackable": false,
    "check_minimum_stack_size": true,
    "check_maximum_stack_size": true
  },
  "remove_defaults": false,
  "filler": {
    "enable_filler": false,
    "reset_stacks": false,
    "run_once": true,
    "tag_priority": true,
    "tags": {
        "#minecraft:logs": 16,
        "#minecraft:planks": 32
    }
  },
  "sort_items": true,
  "items": {
    "minecraft:egg": 64,
    "minecraft:red_bed": 16,
    "minecraft:ender_pearl": 32,
    "minecraft:tnt": 1
  }
}

FAQ

How to install Stacknator?

Install Fabric for your Minecraft version, download Stacknator for the same version and loader, put the file into the mods folder and launch the game with the loader profile.

Which Minecraft versions does Stacknator support?

Stacknator has builds for Minecraft 1.21–26.3.

Is Stacknator needed on the server?

Server only — players don't need to install it

License and source
MIT Licensefree to use and share with credit to the author
Original — Modrinth↗Files unchanged, verified with SHA-512Is this your mod? For rights holders

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