Chord Progression Builder for Songwriters

Song Cage uses music theory, not a machine learning model, to generate chord suggestions. When you select a position on the timeline, the app reads the chord before it, the chord after it, and the melody notes at that beat, then scores every available chord based on harmonic context, voice leading smoothness, and common cadence patterns. The result is a chord progression generator powered by the same theory a trained musician would use.

Song Cage’s chord palette spans three categories: diatonic chords (the chords naturally in your key), borrowed chords from parallel modes (modal interchange), and secondary dominants with resolution arrows showing where each one wants to go. Each chord also has extensions like maj7, sus2, sus4, add9, and more, suggested only when they improve the voice leading from the previous chord.

Yes. Song Cage works as a chord progression generator that suggests chords based on your musical context rather than generating random sequences. Pick a key, place your first chord, and the palette immediately ranks what should come next, factoring in the chords around it and any melody notes you've written. You stay in control of every choice while the app handles the theory.

Yes. If you already have a melody on the grid, Auto Chords harmonizes it in one click: Song Cage reads your notes and generates a full chord progression above them, ranked by how well each chord fits the melody. You choose how often the chords change, reshuffle for a fresh set, and swap any chord for another that fits. It is a melody-first chord progression generator, so the chords follow the tune you already wrote.