NetUtils
by m.shl
NetUtils is a client-side debugging toolkit for inspecting and manipulating the Minecraft networking layer, built on Architectury API for Fabric, NeoForge and Quilt.
What it does
Tools in NetUtils sit between the client and the server, letting a player delay or hold outgoing packets, desynchronize open screens and read internal menu state such as sync IDs, class names, slot metadata and villager trade lists. These actions are things a vanilla client cannot do on its own, so the mod is aimed at protocol study and testing rather than gameplay.
Developers and researchers can send raw packets in a loop, and a custom command prefix typed into the regular chat field handles the lower-level calls. A resource pack option can refuse server-requested packs so a test environment stays isolated. Required dependencies are Architectury API, Kotlin and Kotlin for Forge, and Mod Menu is optional. Environment is client-side only, so servers need nothing, and the code is released under the MIT License as open source. Files cover 1.21 – 1.21.11 across Fabric, NeoForge and Quilt, with 1.0.2 for 1.21.11 as the latest build on each loader.
Key features
Packet flow control
Outgoing packets can be intercepted, delayed or fully held, which makes it possible to measure how a server responds to slow traffic.
Inventory state manipulation
Screens can be closed locally without notifying the server, reproducing a desynchronization case for testing state handling.
Detailed data extraction
Menu internals are visible, including sync IDs, class names, villager trades and the metadata of individual GUI slots.
Network resilience testing
Desynchronization and delay tools can be combined to check whether a server's anti-cheat and state-recovery logic holds up.
Enhanced client-side commands
A custom command system with its own prefix covers low-level interaction, including raw packet sending in a loop.
Restore last closed screen
Pressing V reopens the last screen that was closed, which helps when a desynchronization leaves the interface out of step.
Gallery
Compatibility
Latest build for each game version and loader.
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 2
Optional 1
Use cases
Who it’s for: NetUtils suits Minecraft developers, protocol researchers and server developers who test anti-cheat and state handling. It is not a gameplay mod, and players who only want quality-of-life changes will find little here.
Questions
Does NetUtils need to be installed on the server?
What does NetUtils require?
Which loaders and versions does NetUtils support?
In the catalog
NetUtils is one of 4,058 Storage mods on ModsFinder, and one of 2,474 Storage mods for Fabric. 19,862 mods support Minecraft 1.21.11.
Similar mods
What the author says
A powerful networking utility for Minecraft protocol debugging, state synchronization testing, and network analysis. Built on the Architectury API for Fabric and NeoForge. Press V to restore the last closed screen.
Official listing
- Modrinth page
- modrinth.com/mod/netutils
- Owner
- m.shl
- Published
- 2025-12-25
- Updated on Modrinth
- 2025-12-28
- Facts verified
- 2026-10-15