RNG Chords

RNG Chords is a playful browser-based random chord generator for guitarists, pianists, songwriters, and producers.

It mixes dice-driven harmony generation, instant browser playback, MIDI export, and a lightweight sketchpad workflow so you can find a happy accident, keep the good bits, and build from them fast.

Why it exists

Sometimes you want a fresh progression without opening a full DAW session or overthinking theory first.

RNG Chords helps you:

• Roll a first idea in seconds
• Keep the chords that feel good
• Reroll the weak spots
• Hear the result right away
• Export MIDI when the idea is worth keeping

Who it is for

• Guitarists who want fresh voicings and quick progression seeds
• Pianists who want colorful harmony without menu-diving through plugins
• Songwriters who want verse, chorus, or bridge ideas fast
• Producers who want a quick harmonic sketch before arranging

What it does

• Roll guided or advanced chord progressions
• Preview single chords and play full ideas in the browser
• Switch between multiple playback instruments
• Keep or reroll individual chords
• Save idea snapshots into A, B, and C slots
• Restore your last creative session after refresh
• Change rhythm feel without rebuilding the whole progression
• Toggle lightweight theory labels
• Build chords manually or paste typed chord symbols
• Export ideas as MIDI

Example outcomes

• Indie-pop lift with bright major color and quick movement
• Neo-soul drift with richer extensions and smoother motion
• Cinematic tension with darker harmony and a slower release

Tech stack

• Astro
• React
• Motion
• Tone.js
• Bun

Getting started

Install dependencies:

bun install

Start the dev server:

bun run dev

Build for production:

bun run build

Run the full check suite:

bun run lint && bun run typecheck && bun test

Start fast

• Pick an instrument focus that matches how you play
• Choose Easy, Color, or Spicy chord complexity
• Click Roll First Idea or Surprise Me

Roll ideas

• Use Roll First Idea, Roll This Setup, or Roll New Idea depending on where you are in the app
• Use Surprise Me to randomize the musical setup and playback instrument

Shape the progression

• Use Keep to pin a chord you like
• Use Reroll on a single slot for a fresh replacement
• Use Reroll Unlocked to refresh only the chords you did not keep

Compare versions

• Save the current idea into slot A, B, or C
• Click a filled slot to load that saved version back in

Play and preview

• Pick an instrument and tempo in the playback panel
• Change the rhythm Feel to reshape playback phrasing
• Use Play, Stop, and Loop to audition ideas
• Use Export MIDI when you want to continue elsewhere

Manual input

• Use the manual builder if you already hear a chord shape in your head
• Paste typed chord symbols like Cmaj7, Am7, D7, Gmaj7
• Mix manual input with rolled ideas when you want a more directed progression

Keyboard shortcuts

• Space — play or stop
• ← / → — preview neighboring chords
• Enter — replay the selected chord preview

Project structure

/
├── docs/
├── public/
├── src/
│   ├── components/
│   ├── lib/
│   ├── pages/
│   └── styles/
├── tests/
└── package.json

Notes

• The app is designed for fast ideation, not strict theory-first composition
• Playback uses browser audio, so the first interaction may need to unlock audio on some browsers
• Social sharing metadata becomes fully absolute when SITE_URL is set for production