Ask HN: Is there any interactive instrument teaching website?

Honestly, just find a local tutor. The money you'll spend on subscription to apps, you're better off meeting a tutor once a week for 30/45 mins and taking it from there. Bad habits can be picked up easily, especially as an adult learner.

Smartmusic.com does exactly this. It's not 100% accurate and is mostly sold to school band programs but they've got a pretty cheap annual hobbyist subscription.

That may not help you a lot but there is for piano. I use Flowkey and the app does more or less that. I don't know if the sound recognition is very good, I use it with midi and not the microphone because I play with a headset.

Thanks, so you are using midi keyboard and the app checks midi notes if it is correct etc., rigth? I will take a look.

Yes, it's not extremely advanced but it's more than good enough for me.