Stacknator
by Riser876
Stacknator lets server owners raise or lower the maximum stack size of vanilla and modded items through a single JSON configuration file.
What it does
Stacknator changes the stack size of items during game initialization, by editing their item data components rather than patching code at runtime. Stack sizes are set in a file named stacknator.json, which the server reads when it starts loading a world. Items can be targeted by identifier, and tag identifiers can be used to apply a size to a whole group of items at once.
The mod covers both vanilla items and items added by other mods, so a modpack can use one configuration for everything it contains. A filler mode can apply rules to every registered item, enforcing the configured checks, and it can optionally run only once. Logging can record each successful change, while failures are always logged. Fabric API is required and must be installed alongside the mod.
Stacknator is published for Fabric only, across 17 release versions, with 2.0.1 for 26.3 as the latest file. It is server-side only, so players join without installing it. The code is open source under the MIT License and is published with a public source repository and issue tracker.
Key features
Vanilla and modded items
Maximum stack sizes can be set for vanilla items and for items added by other installed mods.
Single configuration file
Every custom size is defined in stacknator.json, with item and tag identifiers as keys.
Configurable validation checks
Separate toggles enable or disable checks for damageable, stackable, minimum and maximum stack size.
Filler and reset options
A filler can apply rules to all registered items, and a reset option restores default sizes over custom values.
Compatibility
Latest build for each game version and loader.
26.x5 of 5 versions with builds
1.21.x12 of 12 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 1
Use cases
Who it’s for: Server owners and modpack authors who want to change how many items fit in a stack, across vanilla and modded content, without editing each mod.
How it compares
Stack Size Tweaks is open source under the MIT License, works on Fabric and NeoForge, and runs on client and server. Balanced Stack Sizes is open source under the MIT License, is published for Fabric only and covers 1.21.3. StackPlus is open source under the MIT License and needs the client, while the server may skip it, for Fabric and NeoForge.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Stacknator | Fabric | 1.21 – 26.3 | Server-side only | 2026-06-20 |
| Stack Size Tweaks | Fabric and NeoForge | 1.21 – 26.3 | Client and server | 2026-09-25 |
| Balanced Stack Sizes | Fabric | 1.21.3 | Client and server | 2024-12-01 |
| StackPlus | Fabric and NeoForge | 1.21 – 26.3 | Client required, server optional | 2026-09-17 |
Questions
Does Stacknator need Fabric API?
Does Stacknator have to be installed on the client?
Which versions does Stacknator support?
In the catalog
Stacknator is one of 4,058 Storage mods on ModsFinder, and one of 2,474 Storage mods for Fabric. 8,071 mods support Minecraft 26.3.
More from Riser876
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What the author says
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…
Official listing
- Modrinth page
- modrinth.com/mod/stacknator
- Owner
- Riser876
- Published
- 2025-04-10
- Updated on Modrinth
- 2026-06-20
- Facts verified
- 2026-10-15