Muon is a lightweight alternative to Electron written in Golang in about ~300 LoC, using Ultralight instead of Chromium. Ultralight is a cross-platform WebKit rewrite using the GPU to target embedded desktop applications that resulted in a fast, lightweight, and low-memory HTML UI solution that blends the power of Chromium with the small footprint of Native UI.


  • Full JS to Go interop
  • GPU based rendering
  • Cross-platform
  • Hot-reloading
  • Superior disk size + memory & cpu usage

Comparison with a "Hello, World!" React App

Muon Electron
CPU 0.0% 1.2%
MEM 26.0 MB 201.7 MB
DISK 42 MB 136 MB


From examples/create-react-app/main.go:

package main

import (


func main() {
  // Any static asset packer of your liking (ex. fileb0x)
  fileHandler := http.FileServer(webfiles.HTTP)

  cfg := &muon.Config{
    Title:      "Hello, World!",
    Height:     500,
    Width:      500,
    Titled:     true,
    Resizeable: true,

  m := muon.New(cfg, fileHandler)

  // Expose our `add` function to the JS runtime
  m.Bind("add", add)

  // Show the Window and start the Runtime
  if err := m.Start(); err != nil {

// Muon automatically handles interop to and from the JS runtime
func add(a float64, b float64) float64 {
  return a + b


Q: How are JS types translated to Go types?

  • JS: Boolean Go: bool
  • JS: Number Go: float64
  • JS: String Go: string
  • JS: Object Go: struct via JSON

Q: I get exit status 3221225781 when I try to run my program

  • Your program likely can't find the Ultralight libraries. Ensure they're either installed on the system, or, in the same folder as your program. Currently, Muon uses the 1.1 Ultralight pre-release that hasn't yet propagated to their main site and can only be downloaded from the Ultralight github repo.

Q: How do I get rid of the Console window on Windows?

  • Add -ldflags -H=windowsgui to either your go build or go run to get rid of the window.

Q: How do I setup Ultralight?

Q: Is there perfect Chrome or Firefox feature parity?

Q: My program can't find, even though it's in the same directory

  • Add -ldflags "-r ." to your go build to set rpath to the local directory for library resolution.