Online Keyboard Synth

Online Keyboard Synth puts a synthesizer in a browser tab. Click Enable sound, then press the letters printed on the piano keys: Z, X and C start the lower white keys, Q to I covers the upper row, and number keys play the black notes. Space acts as sustain, Lower and Higher shift the octave, and Escape releases every note. On a phone you tap the keys directly, and a MIDI keyboard plugged into a supporting browser works as well.

The presets give you a quick sense of range, from Retro Lead and Deep Bass to Glass Keys, Strings Pad and Brass Stab. Open the sound design panel and you can change the waveform, the brightness (filter cutoff) and resonance, the attack, decay, sustain and release, and the amount of reverb and delay. Sounds you build can be saved in your browser, and the recorder captures a take you can download.

The most distinctive part is the set of five short lessons. Each covers one idea in two steps: oscillators and waveforms, the filter, the ADSR envelope, reverb and delay, and detune, and finishes with your hands on the controls. The filter lesson, for example, loads the Deep Bass preset with the cutoff at 640 Hz and asks you to hold Z while turning the brightness up so you hear the sound open. It's a good way to connect the jargon to what you hear, and the synth keeps responding throughout.

The about page is clear about scope. This is a focused instrument, not a digital audio workstation, so there is no multitrack editing, plugin hosting, account or cloud backup. Recordings live in page memory until you download them and disappear on reload. It also notes that browser and device behaviour it hasn't tested is recorded as unverified.

The privacy page says notes and recordings are processed on your device using the browser's own audio, MIDI and recording features and are never sent to a server. There's no sign-up, the site sets no cookies, and analytics come from a cookieless, self-hosted Plausible installation.