Bfxr: Free Sound Effects Generator for Games and Apps

Every time I start a new small game or app I hit the same wall: the visuals look decent, the logic works, but it's completely silent. Asking the agent to "add some sounds" usually ends in one of two ways — it either imports a giant audio library and starts writing JavaScript synthesis code, or it produces a single beep that sounds like a broken microwave. Neither of these is what I wanted.

Bfxr is the thing I reach for now. It's a sound effects generator that runs in your browser at bfxr.net — no installation, no account, no code to write. You click a category (Explosion, Jump, Pickup, Laser...), hit Randomize until you get something you like, and download a WAV file. That's the whole workflow. The tool has been around for years and is one of the go-to tools in the indie game dev world for exactly this kind of thing.

The original bfxr was built in Flash (ActionScript), and was itself based on an earlier tool called Sfxr by DrPetter. In 2025 the author rewrote it in JavaScript, so the live site at bfxr.net now runs a modern, browser-native version. The GitHub repo for the original Flash version still exists with 1000+ stars — the new JS version lives at increpare/bfxr2, but the easiest entry point is just the website.

1How to use bfxr to get sound files

2What sounds can bfxr generate

Bfxr covers the most common game sound categories out of the box. Pickup sounds for collecting coins or items. Laser and shoot sounds for projectile effects. Explosions of various intensity. Powerup jingles. Hit and hurt sounds — the short crunch you hear when something takes damage. Jump sounds. And blip or select sounds for UI clicks and menu navigation. The footstep generator (added in bfxr2) is a seperate panel that produces surprisingly natural-sounding step sequences for different surfaces. All of this is retro/8-bit in character, wich is exactly the aesthetic most vibe-coded games go for anyway.

3What to tell your agent

I downloaded a WAV file from bfxr.net and put it at /public/sounds/jump.wav. Add code to play this sound whenever the player jumps. Make sure the audio loads without blocking the page.

I have these WAV files in /public/sounds/: coin.wav, jump.wav, explosion.wav, hit.wav. Wire each one up to the appropriate game event. Use HTML5 Audio API, no external audio libraries.