Futures Screener

Real-time Binance Futures screener with order book density analysis, signal detection, and charting.

Architecture

futures-screener/
├── server/           # Node.js Fastify API (port 3200)
│   ├── index.js      # Main server, routes, Binance API integration
│   ├── signals.js    # Signal engine (vol_spike, liq_sweep, oi_div, funding_squeeze)
│   ├── liq-sweep.js  # Liquidity sweep detection (swing-only, volume gate)
│   ├── densityV2.js  # Order book density V2 (adaptive buckets, σ walls)
│   ├── ws.js         # WebSocket manager (Binance market streams)
│   ├── auth.js       # JWT auth + Google OAuth
│   ├── push.js       # Web Push notifications (VAPID)
│   ├── state.js      # In-memory state management
│   ├── klines-cache.js # Kline cache layer
│   └── modules/      # Binance API wrapper, density detector/tracker
├── app/              # Frontend (vanilla JS, no framework)
│   ├── index.html    # SPA entry
│   ├── app.js        # Core UI logic
│   ├── mini-charts.js # LWC v5 charts (259KB, main visualization)
│   ├── signals.js    # Signal UI
│   ├── settings.js   # Settings panel (30+ options)
│   ├── drawing-manager.js # Chart drawing tools
│   └── sw.js         # Service Worker (push + caching)
├── data/             # SQLite DBs (signals, push_subscriptions)
└── docs/             # VISION, ROADMAP, UI-SPEC, STATUS

Quick Start

cd /home/app/futures-screener
npm test              # Run smoke tests
node server/index.js  # Start server (or PM2: futures-screener)

Key Commands

• Start: pm2 start futures-screener
• Logs: pm2 logs futures-screener --lines 50
• Test: npm test
• Lint: npx eslint server/ --ext .js (if configured)

Tech Stack

• Backend: Fastify 5, better-sqlite3, jsonwebtoken, ws, web-push
• Frontend: Vanilla JS, TailwindCSS, lightweight-charts v5
• Data: Binance Futures REST + WebSocket (FAPI, public endpoints)
• Deploy: PM2, Nginx reverse proxy, Let's Encrypt SSL
• Domain: futures-screener.szhub.space

Code Conventions

• const > let, never var
• async/await everywhere
• Response format: { success: true, data: {} }
• Logs: [ISO timestamp] prefix
• No frameworks on frontend — vanilla JS with DOM manipulation

Signal Types

Signal	Logic	Confidence
vol_spike	Volume ≥5x 20-period avg	40-100
liq_sweep	Swing level + volume gate + OI drop	35-100
oi_divergence	Price/OI divergence (exhaustion/accumulation)	40-100
oi_funding_squeeze	OI spike + extreme funding (contrarian)	40-100

Important Context

• Rate Limiter: 3-tier Binance protection (soft 1800, hard 2200, pause on 429/418)
• WebSocket: /market/stream endpoint (not legacy /stream)
• Frontend caching: Memory → IndexedDB → Server (3-tier)
• Signals are server-side — client only filters/displays
• No tests existed before — tests/ directory is new

Environment Variables

See .env.example — key ones: JWT_SECRET, VAPID_*, PORT (default 3200)

Recent Major Changes

• LWC v5 migration (chart API changes)
• Keltner + Regression channel overlays
• Liq Sweep V2 (swing-only, volume gate ≥5x)
• 3-tier IndexedDB cache + infinite scroll
• Web Push (VAPID, server-side filtering)