Tnx for the feedbacks.
The app is intentionally minimalist and intend to serve but one goal: give everyone the possibility to practice chord progressions 
. The purpose is purely educational.
Most the ideas above are really great but won’t be added to CHRDS. First because there is already a lot of vst/standalone apps that do that kind of advance stuff very well:
The other other reasons are music-teaching related:
Of course it would be fun but also a non-needed distraction for my young students 
. I wanted the sound to be kind of neutral (and also not a piano because the idea is that you don’t have to be a pianist to play around with harmony).
That could be implemented though, or at least adding something to keep track of the progression you just played. I need to think about it.
That is more subject to debate (in an educational point of view). I conceived a similar app with MAX/MSP some years ago with a keyboard showing the notes of the chords. The problem is that students tended to just copy the notes of the piano in their DAW without even thinking about intervals and chords content . I really don’t want to give them everything so easily (as i said before, they are kind of lazy ahah). They need to think about what they do in order to deeply acquire that harmony knowledge. But maybe should i add some informations about chords in the help section?
Not at the moment, for the same reasons than notes displaying.
Ok That is a good idea. It could be very playable with a grid or even with a computer keyboard. It could do all kind of stuff like arpeggios, MIDI etc etc… That may be one of my next projects 
