Stack Manager — configurable stack sizes (vanilla + mods)

A lightweight server-side mod that generates a config with all items (vanilla + modded) and lets you set the max stack size per item. Works in singleplayer (integrated server) and on dedicated servers.

Features

Generates config/stackmanager_items.json with every registered item.
Per-item stack limits you can edit at any time.
Auto-adds new items from newly installed mods on startup/reload.
Safe network cap = 99 to avoid protocol/NBT issues.
Optional in-game commands (enabled when Fabric API is present).

Commands (optional, require Fabric API)

/stackmanager reload — reload the config and append any missing items.

/stackmanager set <id> <value> — set a new limit (clamped to 99).

/stackmanager set <id> default — restore the game/mod default (clamped to 99).

Without Fabric API the mod still works; edit the file and restart (or reload using your preferred method).

Config file

Path: config/stackmanager_items.json

{
  "formatVersion": 1,
  "items": {
    "minecraft:acacia_button": 64,
    "minecraft:oak_planks": 99
  }
}

Keys are full item IDs (namespace:item).
Values are clamped to 1–99 at load time.

Handy editor shortcuts for `stackmanager_items.json`

(VS Code / most editors; Windows/Linux = Ctrl, macOS = Cmd unless noted)

Format document (auto-indent JSON):
Shift+Alt+F (Win/Linux) · Shift+Option+F (macOS)
Find / Replace:
Ctrl+F / Ctrl+H · Cmd+F / Cmd+Alt+F
Select next occurrence (multi-cursor):
Ctrl+D · Cmd+D
Go to line:
Ctrl+G · Cmd+G
Select word / line:
Ctrl+W (word) / Ctrl+L (line) · Option+Shift+→/← or Cmd+L (macOS)

Tips

Keep IDs alphabetized for easier diffs.
Use regex replace in Ctrl+H to mass-edit values.
After editing, run /stackmanager reload (if commands available) or restart the world/server to apply changes.

Compatibility & limits

The mod enforces limits on the server; clients don’t need the mod (unless other mods require it).
Items with different NBT (custom names, enchantments, damage, etc.) never stack, by vanilla rules.
Most vanilla and modded GUIs respect these limits. If a specific mod screen still caps at 64/99, report it—small per-screen patches are possible.
Values above 99 are intentionally reduced to 99 to keep networking stable.

Requirements

Fabric API: optional but recommended for better experience (enables /stackmanager commands and smoother reloading).

Recommended usage

Install Fabric API (recommended, not required) to use in-game commands and improve quality of life.
Edit values directly in the config file before starting a world/server. Command-based changes—especially without Fabric API—can be cumbersome and may require restarts or extra steps.

Ideas for using the mod (easier vs. harder gameplay)

Potions

Easier: set potions to 16 or 32 per slot
minecraft:potion: 16
minecraft:splash_potion: 16
minecraft:lingering_potion: 8–16

Benefit: fewer inventory trips during raids, mining, and boss fights.

Note: Potions carry NBT (effect type). Only identical potions stack.

Other quick ideas

Builder / mega-projects (QoL):
Blocks (stone, planks, glass, terracotta) 99; food 64–99; firework_rocket 64–99.
Exploration / Elytra:
Rockets 16 (harder) or 64–99 (easier); Ender Pearls 16–32 (easier) or 8 (harder).
Combat / PvE:
arrow 99; snowballs/eggs 64–99 for events/minigames.
Economy / survival challenge:
Ores/ingots 16; ore blocks 8; pearls/snowballs 8 to curb spam

FAQ

How do I find an item ID?
Enable advanced tooltips with F3 + H, then hover the item: you’ll see namespace:item.

Can I set 9999?
No. For network safety the effective cap is 99.

Singleplayer or server?
Both. In singleplayer, drop the mod into mods/. On a dedicated server, only the server needs the mod.

Contact: https://github.com/Neni-o/issue-tracker

Stack Manager (Fabric/NeoForge)