ScaleInKey

ScaleInKey is an Android (8+) app that shows you the notes and chords in various modes and scales. It also includes a simple chord progression sequencer with looping and adjustable BPM.

Features 33 scale types across six categories — the 7 diatonic modes, Harmonic/Melodic Minor, five Pentatonic & Blues scales (Major/Minor Pentatonic, Major/Minor Blues, Egyptian Pentatonic), ten World/Exotic scales (Hungarian Minor, Byzantine, Persian, Hirajoshi, In Sen, Iwato, Enigmatic, Phrygian Dominant, Neapolitan Minor, Neapolitan Major), six Jazz scales (Altered, Lydian Dominant, Lydian Augmented, Locrian ♮2/Half-Diminished, Bebop Dominant, Bebop Major), and three Symmetric scales (Whole Tone, Diminished Whole-Half, Diminished Half-Whole) — with correct enharmonic spelling in every key. Diatonic chords for every scale that supports them, shown as triads by default with a per-chord toggle to the 7th-chord voicing, including the rarer harmonic/melodic-minor chord qualities (minor-major7, augmented-major7, fully-diminished7, half-diminished7). Four instrument diagrams — Piano, Guitar, Ukulele, Bass — highlighting the current scale or selected chord. Fingering-chart mode for Guitar/Ukulele/Bass: switch from the full-neck highlight view to a traditional chord-box diagram for the selected chord (using real, curated open-position shapes where one exists, and an algorithmic near-the-nut search otherwise so every chord — even exotic ones — still gets a playable shape), or a finger-numbered scale-position box when no chord is selected. Bass shows a single root-note position marker instead, since bass isn't played as strummed chords. Tap-to-hear playback of any note, chord, or fretboard/chord-chart position, via a real SF2 synth (not a beeper) — bundled with a small default soundfont, with the option to load your own .sf2 file. Every tap flashes a distinct highlight color so it's clear exactly what you hit. Chord progression sequencer — a separate screen (switch to it via the 🎹 icon next to the title) for building an ordered sequence of the current scale's diatonic chords and playing it back at a settable tempo: a BPM stepper (default 120), beats-per-chord, a loop toggle, tap to append a chord from the palette (long-press to toggle its triad/7th voicing first), and drag-to-reorder or tap-to-remove on chords already queued.