A Game Boy sound chip in a browser tab. Feed it any song.
Wario Synth is a free online 8-bit synthesizer. Under the hood is a software model of the Game Boy's four-channel APU:
Give it a MIDI and it decides which part goes to which channel, then renders the lot with Web Audio oscillators. No plugin, no download, no account.
v1 is tuned to sound good on anything — it takes liberties with the hardware to keep melodies clear. v2 beta is the purist's engine: strict duty cycles, real wavetables, hardware-accurate noise. Same MIDI, two flavours. Both are in the app.
Search a song title and Wario Synth finds a MIDI online, or upload your own. Generate, listen, then Save Audio (WAV) or Save MIDI. Share links carry the song so friends hear the same version.
Handy for game jams, ringtones, demo-scene sketches, or just hearing what your favourite track sounds like on a 1989 handheld.
Is this a real Game Boy emulator?
No. It's a synthesiser modelled on the Game Boy's sound chip, running on Web Audio. v2 beta gets closest to the hardware.
Can I play it live with a keyboard?
Not yet. It plays MIDI files — search a song or upload your own.
Does it work on phones?
Yes, including iPhone. Turn silent mode off and tap Enable Audio if it's quiet.
Can I download what it makes?
Yes: WAV audio or a Game Boy-arranged MIDI, both from the app.