Dokko's Hotbar Optimizer

The mod changes how the client handles hotbar slot selection. In vanilla Minecraft the client waits up to 50 ms, one game tick, before it reports a slot change to the server. This client-side mod drops that wait and transmits the change right away. The stated effect is that the server learns sooner which item is held, which can make totem checks and attribute swaps line up more closely with what the player does.

The author reports a reduction in ghost totem occurrences of 71 percent on a 20 ms connection and about 25 percent faster sync on a 150 ms connection. These are the author's own measurements and are not verified here. The change affects gameplay in several areas, including PvP and crystal fights, where hotbar actions feel more responsive. Because it alters timing sent to the server, the author notes that servers may not allow it and that players should ask the server owner before using it.

Dokko's Hotbar Optimizer is published for Fabric and Quilt, with 11 release versions across 1.20.5 – 1.21.8. Files target the 1.20.5, 1.20.6 and 1.21 – 1.21.8 builds. It is released under the CC0 1.0 Universal license, and its source code and issue tracker are public.