XotoPad might be a bit more popular than Pianu. We know about 1 link to it since March 2021 and only 1 link to Pianu. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
MIDI devices mostly refer to musical controllers. With it, you can plug a controller and play piano on https://pianu.com, for example. I use it sometimes. - Source: Hacker News / almost 3 years ago
I think I know what you are asking for. Searching finds me this. I have no experience with using this however, but maybe trial it: https://feelyoursound.com/xotopad/. Source: over 1 year ago
Flowkey - The easiest way to learn piano with your iPhone or iPad
Navichord - Intuitive chord sequencer and MIDI controller for iOS
Simply Piano - Fast and fun way to learn piano
IsoPad - IsoPad lets you use your Windows tablet to play electronic MIDI instruments.
Touch Pianist - Play piano like a pro without playing piano.
TouchDAW - Full-featured DAW control and general purpose MIDI control app.