Negative Harmony is an app designed to simplify the understanding and visualization of the musical theory of negative harmony. It offers a selection of all western scales and modes, over 10 different chord types, and sound examples for each chord (positive and negative). The app also includes diatonic note detection and an indicator for notes and chords outside of the selected scale. With its easy-to-understand UI design, Negative Harmony makes it easy for users to grasp the concept of negative harmony.

The app consists of two pages: Scales and Chords.

On the Scales page, users can select a scale or mode and tap on a key inside the circle of fifths to display the selected combination. The app then shows all the notes inside the chosen scale/mode and their relative negative harmony. It also visually represents this relationship on the circle of fifths with a blue axis, which separates the circle into two parts.

The Chords page becomes available after selecting the key and scale on the Scales page. Here, users can choose the desired chord type (major, minor, suspended, augmented, etc.) and select a note from the chosen scale/mode. The app then displays the name of the selected chord, the notes inside the chord, as well as the negative harmony chord name with the notes inside the "negative" chord. Non-diatonic chord notes are displayed in red, indicating notes or chords that are not native to the selected key.