JASS-APP

Real-time MIDI chord detection and suggestion engine. Play chords on a MIDI piano and get intelligent next-chord suggestions streamed to a web UI via WebSocket.

Prerequisites

• Python 3.10+
• Node.js 18+
• A MIDI controller (optional — the backend can run without one)

Setup

Backend

cd backend
pip install -r requirements.txt

Frontend

cd frontend
npm install

Running

1. Start the backend

python backend/main.py

The WebSocket server starts on ws://localhost:8000/ws.

To run without a MIDI device:

DISABLE_MIDI=1 python backend/main.py

2. Start the frontend

cd frontend
npm run dev

Opens at http://localhost:3000.

Configuration

Environment Variables

Create a .env file in the backend directory with the following variables:

# Perplexity API Key (required for song recommendations)
PERPLEXITY_API_KEY=your_api_key_here

# Spotify API Credentials (optional - for album art and artist info)
SPOTIFY_CLIENT_ID=your_client_id_here
SPOTIFY_CLIENT_SECRET=your_client_secret_here

# Optional: Disable MIDI input
DISABLE_MIDI=1

Getting Perplexity API Key

1. Visit https://www.perplexity.ai/
2. Sign up or log in
3. Navigate to your account settings and generate an API key

Getting Spotify Credentials

1. Visit https://developer.spotify.com/dashboard
2. Log in or create a developer account
3. Create a new application
4. Copy the Client ID and Client Secret
5. Add them to your .env file

Note: Spotify credentials are optional. Without them, song recommendations will still work but won't display album art or artist information.

Project Structure

backend/
  main.py              # FastAPI WebSocket server + MIDI capture
  jass/                 # Chord suggestion & tonal tension engine
  pianomidi/            # MIDI input & chord detection utilities
  requirements.txt

frontend/              # Next.js + React + Tailwind CSS
  src/app/