NoteFinder is an ear training app, where the exercise is to guess a tone from various scales.
The inspiration for this has been a similarly named exercise in Yousician app, where I thought that the exercise is some fun, but with very little features / variability. Moreover, I could not find any other app that would do something similar and have the features I like (onscreen piano keyboard, variability in scales & keys, nice statistics), so I decided to build it myself.
I am submitting to ShowHN to check whether it is fun / useful for others as well, so any feedback is greatly welcome.