SongParts

Sketch > Arrange > Export

By Miguel Feraso Cabral

BPM120

KEYC MAJOR

BAR1.1

LOOPOFF

Chord Rack

KEY

TIME /

PROG

BPM120

SWING0%

VOL80%

SNAP

TOOL

Generator Rack

GENERATION SCOPE

SongParts is a fast songwriting sketchpad that helps you turn musical ideas into complete song foundations. Create melodies, generate chord progressions, bass lines and accompaniment parts, experiment with different harmonic and rhythmic variations, and quickly explore alternative arrangements. When you find something worth developing, export everything as MIDI and continue refining your work in your favourite DAW.

Chords (left panel)

Type a chord (e.g. Dm7, G/B) and click ADD, or pick one from the palette.
On a card: reorder, − + length, duplicate, remove. Double-click the name to edit.
Set KEY and TIME. DETECT guesses the key from your notes.

Edit notes (piano roll)

TOOL: SEL select/move · PEN draw · ERA erase. (Alt+drag also draws.)
Drag a note to move, drag its right edge to resize, drag empty space to box-select.
Ctrl/Cmd + C/V copy-paste · Delete remove · Ctrl/Cmd + Z undo · Ctrl/Cmd + A select all.
Scroll: wheel = up/down · Shift+wheel or bottom bar = left/right · Ctrl/Cmd+wheel = zoom.
Note colors: your notes · generated · mutated · selected.
Outline = harmony fit: chord · scale · tension · clash.

Loop region (top ruler)

Drag empty ruler = create a loop · drag the middle = move · drag an edge = stretch.
LOOP turns looping on/off.
Shift+click the ruler sets the playhead.

Play

play · pause · stop · SEL plays only the selection. Space = play/pause.
Adjust BPM, SWING, VOL. Edits made while playing are heard immediately.

Generate parts (right panel)

Pick a SCOPE (entire song / loop region / selected notes).
In a module (Bass / Harmony / Arpeggio / Melody) set the sliders and click GENERATE.
Generated tracks are ADAPTIVE — change a chord and they follow. Per track switch ADAPT / ASSIST / MANUAL and toggle Mute · Solo · Lock · Visible.

Experiment & save

NOTE OPS: mutate, quantize, humanize, transpose, invert… on the selection.
VERSIONS A/B/C/D switch ideas instantly · SNAPSHOTS save/restore states.
SAVE/OPEN a project (JSON) · set AUTOSAVE.
EXPORT TRACKS (one .mid per part) or EXPORT ALL (single file) → finish in your DAW! :)

Created, designed and developed by
Miguel Feraso Cabral
June 2026

Written in HTML, CSS and JavaScript.
Powered by the Web Audio API and Tone.js.