This tool can generate fretboard visualizations that might help you to improve your harmony guitar skills.

The main idea is to emphasize the correct notes over the chord played in background. So seeing these notes in the fretboard and knowing when the chord changes you could be in the correct place by changing your target notes, even if you are playing in the same scale.

Select the key center and the scale you'd like to play in, and also the chords you'd like to visualizate.

NOTE: To mantain a clean visualization, the maximum number of chords you can select is four.