SneakFix
Simple mod that ignores the visual acknowledgment packets for crouching because it desyncs and makes the player crouch twice on the client end.
Screenshots
About this Mod
Ever since the crouching animation was added this bug has existed:
https://bugs.mojang.com/browse/MC-159163
It's because the server sends back the visual starting and stopping crouching animations when the player crouches, but information takes time to travel and it is trivial to crouch and uncrouch before the server sends those packets back. This causes a visual desync on the client end.
Don't believe me? (Speedbridgers know this all too well)
Load up a world or join a server after version 1.14 and tap your crouch key very quickly. (as in press crouch and quickly uncrouch, not spam it). You will notice and extra crouch animation much of the time.
BTW
This mod borrows code from sneak tweaking here:
https://www.curseforge.com/minecraft/mc-mods/sneak-tweak
so if you want more functionality to tweak how crouching works, then go there. I just wanted to fix a bug not a bigger mod with dependencies.
Available Versions
How to Install SneakFix on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set fabric Loader
In the panel under "Egg", select the fabric loader and matching Minecraft version (1.21.4).
Install Mod
Open the mod browser in the dashboard and search for "SneakFix". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
1.21.4, 1.21.3, 1.21.2 (+3 more)
Server-side
✗ UnsupportedRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
SneakFix server crashes on startup – what to do?
Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21.4). You can switch loaders with one click in the panel.
Is SneakFix compatible with fabric?
SneakFix officially supports fabric for Minecraft 1.21.4, 1.21.3, 1.21.2. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with SneakFix – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if SneakFix consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
Similar Mods
Rent Modded Server
Install SneakFix with just one click on your server.