Hi Product Hunt, I built MonoSynth because I wanted a real synthesizer I could share with anyone via a single link. Most browser synths are either basic toys with four knobs or samplers disguised as synths, so I built what I actually needed: full semi-modular synth modeled on classic dual-VCF semi-modular hardware, complete with a patch bay that behaves like actual equipment. The patch bay is the core feature. MonoSynth uses normalled routing by default-jacking a cable in physically overrides the path rather than summing signals together. With 12 normals and 35 patch sockets, you can route everything manually right on the panel. Under the hood, every signal is treated as raw voltage. Audio, CV, and gate signals share the exact same stream, scaled to actual volts. Patching audio into a CV input behaves just like it does on physical hardware. The filters, oscillators, and envelopes run as custom AudioWorklets instead of stock Web Audio nodes, giving you clean, alias-free oscillators and true filter self-oscillation. It's completely free, requires no account, and runs entirely in the browser with zero installation. Built with TypeScript and Web Audio, it carries only a single runtime dependency. You can play it using your mouse, touch screen, computer keyboard, or MIDI controller. Patches save locally, export to file, encode directly into shareable links, or print into a clean two-page physical patch sheet complete with cable diagrams. A few honest limitations to note: it is strictly monophonic by design and Web MIDI support requires Chrome or Edge (Firefox and Safari still lack full Web MIDI implementation). On your first visit, an interactive 10-step tour runs over the live interface so you aren't left hunting for controls. I'd love to see what you create with it. If you build a patch you like, click COPY LINK and share it in the comments so I can check it out!

MonoSynth.app

Patch a real semi-modular synth in your browser, free

Patch a real semi-modular synth in your browser, free