2,256,823 Downloads Last Updated: Nov 3, 2019 Game Version: Forge

Intuitive lag hunting!


LagGoggles is a profiler where you can see timings in the world, visually. It comes with a custom GUI using a configurable keybind. It's compatible with SpongeForge and Mixin!
You can use LagGoggles as a player too! This is my attempt to create an understanding of what causes lag on a server to regular players.
I noticed some common misconceptions like having machines spread out over different chunks causes less lag than putting it in one chunk.
With LagGoggles, you can look around and see that alot of small things like pipes or cables cause a tiny bit of lag most of the time, often resulting in more lag than a machine right next to the source would.

LagGoggles can also profile clientside FPS as of version 4.0!


Download: here



LagGoggles enabled normal view
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Video explaining the concept

Massive thanks to Grok DuckFarmer for making this video.


  • Sponge compatible (Try the THIN version first!)
  • Teleporting to sources of lag
  • Client GUI, including overlay and clickable menus
  • Colour scale for easy spotting of sources of lag.
  • Calculations are done on the client, so each client can have a different colour scale.
  • Clientside FPS support!
    • Checks render time for Entities, Tile entities and event subscribers
    • It's very young, but it should give some insight in what may cause FPS issues.
  • Config for client:
    • Custom gradients
    • Colorblindess support
  • Config for server
    • Custom permissions for players (non-operators)



  • Drop the jar in the /mods folder
  • Serverside configuration is not required and has no effect.
  • Clients can edit the config to change the colour scale.


How it works

At startup Mixin handles each class being loaded. On the server side, this mod hooks into the loading mechanism. This is the same mechanism SpongeForge uses, that's why it's compatible.

Entities, blocks and event-subscribers are timed using System.nanotime() before and after the tick() and update() methods. These times are being recorded and sent to the client when the profiler is done.



  • Visualisation of various sources of lag
  • Learn your players to build lag-free bases.



You can download the latest release here. The ONLY difference between THIN and FAT is that FAT ships Mixin, which is a library that LagGoggles needs in order to function. It's possible that another mod already ships Mixin or has another version. Generally speaking, LagGoggles can handle most Mixin releases well. A known mod to ship Mixin is SpongeForge. If you have SpongeForge or another mod that requires a different version of Mixin, choose the THIN release.



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