Find it by how it should feel
Every progression carries the feelings it actually produces, in the words a writer would use. Search them, or wander through them, and hear any card in your key before you commit to it.
1,378 progressions · 107 chords · 74 scales and modes · each one says where it came from
Build the song, section by section
Verses, choruses and bridges, each with its own key if it wants one. Chords show as numerals and as names together, so what you learn in one key carries into every other — change the key and the whole song follows.
While a chord is selected, Songling shows what usually comes next, and what it would do to the line
Sketch the arrangement
Lay the song out on a timeline: harmony blocks, a melody written by hand on a grid as tall as a piano, tracks with their own instrument, colour, volume and effects. Cycle a section and work it until it's right.
Cubase-style keys throughout — the same muscle memory your DAW already taught you
Decide how the chords are played
A chord can land flat, or move: an arpeggio, a pattern, a shape you draw yourself. Whatever you choose follows the chords wherever they go — change the progression and the figure comes with it.
Per-note velocity, meter-aligned shapes, and a roll you can edit like your DAW's