← All news·2026-08-09·3 min read

jsfx: Free Retro Game Sound Effects Generator for Browser Games

jsfx generates classic 8-bit game sounds in the browser — coin, laser, explosion, powerup, jump. Open the web interface, design sounds with sliders, copy the config, and your agent adds them to any game.

soundvibegamegithubassets

I was testing a small browser game I built with an agent — enemies moving, score counter working, collisions detecting — and the whole thing felt weirdly flat. Turns out your brain expects sounds. A coin collect without a ping sounds like a bug. An explosion without a boom just looks like a disappearing sprite.

jsfx is a JavaScript sound effect generator that runs entirely in the browser. No files to download, no accounts, nothing to install. It has built-in presets for the classic 8-bit sounds: Coin, Laser, Explosion, Powerup, Hit, Jump, Select, Lucky. You open the web interface at loov.github.io/jsfx, click a preset, tweak the sliders if you want, and get a small JSON description of your sound. That JSON is what your agent uses.

Source

loov/jsfx

★ 584JavaScript

Open on GitHub →

The workflow is unusually vibe-friendly: you design the sound yourself with sliders (no code), then give the resulting config to your agent to integrate. Generation speed is about 10ms per second of audio, so playback is instant. Works in all modern browsers via the Web Audio API.

How to use jsfx in a browser game

1Open the live interface at loov.github.io/jsfx
2Click a preset (Coin, Laser, Explosion, etc.) to hear it
3Tweak the frequency, volume and other sliders until it sounds right
4Click the Add button in the top-right corner and name your sound
5At the bottom of the page, find the JSON config in the input box and copy it
6Give that JSON to your agent along with the code below

Load jsfx and play sounds from config

<script src="https://raw.githubusercontent.com/loov/jsfx/master/jsfx.js"></script>
<script>
var library = {
  "coin":  {"Volume":{"Sustain":0.1,"Decay":0.4,"Punch":0.5}},
  "laser": {"Frequency":{"Start":880},"Volume":{"Sustain":0.05,"Decay":0.2}}
};
var sfx = jsfx.Sounds(library);
</script>

<!-- Play a sound anywhere in your code: -->
<script>
sfx.coin();  // play coin sound
sfx.laser(); // play laser sound
</script>

Use built-in presets directly (no web interface needed)

<script src="https://raw.githubusercontent.com/loov/jsfx/master/jsfx.js"></script>
<script>
var sfx = jsfx.Live({
  "coin":      jsfx.Preset.Coin,
  "explosion": jsfx.Preset.Explosion,
  "jump":      jsfx.Preset.Jump,
  "powerup":   jsfx.Preset.Powerup,
  "laser":     jsfx.Preset.Laser
});
</script>

What to tell your agent

Agent prompt: add retro sounds to a browser game

Add retro sound effects to my game using jsfx. Load the library from https://raw.githubusercontent.com/loov/jsfx/master/jsfx.js via a script tag. Use jsfx.Live() with these presets:
- jsfx.Preset.Coin — play when the player collects points
- jsfx.Preset.Explosion — play when an enemy is destroyed
- jsfx.Preset.Jump — play when the player jumps
- jsfx.Preset.Powerup — play when a power-up is collected
Call sfx.coin(), sfx.explosion() etc. in the appropriate event handlers.

✓What you get

Classic 8-bit game sounds — coin, laser, explosion, jump, powerup — that play instantly in the browser. Design them visually in the web interface, give the config to your agent, and your game stops feeling like a silent prototype. Free, no login, no download.

Source: github.com

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