Hotbar Inventory Transfer

A held key or a single key press sends the item in the selected hotbar slot to the inventory, or pulls matching items back. The transfer works from the game world, so the player never has to open the inventory screen to organize items. Moves are one step, so a full stack can be shifted at once.

Stacking follows a fixed order. Matching items first fill existing stacks that are not full, and only then use empty slots, which keeps the inventory tidy and avoids scattering partial stacks. Overflow is handled so that items are not lost or duplicated when a destination has no room.

Behavior is set under the Options, Controls and Key Binds menus, where a Hotbar Inventory Transfer category lists its keys. The mod is published for Fabric only, on 1.21 – 26.2 with 16 release versions, and Fabric API is required. It is client-side only, so a vanilla server needs nothing and players join without installing it. The code is open source under the CC0 1.0 Universal license.