FastEvent
by ZZZank
FastEvent speeds up the Event system in Forge and NeoForge, one of the most fundamental systems in those loaders, by changing how event handlers are built.
What it does
Forge and NeoForge do not let a mod modify EventBus, because EventBus is loaded as a library rather than as part of the game or Forge itself, so Mixin and transformers cannot reach it. FastEvent works around this limit and optimizes event dispatch inside the loader. Its builds cover 1.16.5 – 1.21.1, with Forge files for 1.16.5 and NeoForge files for 1.21.1.
Event handler construction is faster because FastEvent swaps class generation for lambda construction. The lambdas are hidden from the class listing, which lets the JVM apply more optimization to them. The project includes a JMH benchmark report from a related change made for the Cleanroom project, which used the same approach. Either side can run it, and neither needs it, and the code is open source under the MIT License.
Key features
Faster event handlers
Event handler construction uses lambdas instead of generated classes, which removes one source of slowdown.
Hidden lambda handlers
Lambdas are hidden from the class listing, so the JVM can optimize them more aggressively.
Event system optimization
The mod targets the Event system, which Forge and NeoForge use across the game's event dispatch.
Benchmark report included
A JMH benchmark report from a related Cleanroom change is provided, since per-version test cases are hard to build.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Questions
Does FastEvent need to be on the server?
Which loaders does FastEvent support?
Why are some older builds archived?
In the catalog
FastEvent is one of 3,545 Optimization mods on ModsFinder, and one of 1,441 Optimization mods for Forge. 32,366 mods support Minecraft 1.21.1.
More from ZZZank
Similar mods
What the author says
Long story short, the optimization approach still applies, but Forge/NeoForge does not allow mod to modify EventBus. Unlike classes from Minecraft or Forge itself, EventBus is loaded not as part of the game, but as "library", which makes it impossible to modify EventBus via Mixin or Transformer.
Official listing
- Modrinth page
- modrinth.com/mod/fastevent
- Owner
- ZZZank
- Published
- 2025-05-09
- Updated on Modrinth
- 2025-06-18
- Facts verified
- 2026-10-15