Market Backend (Polygon)

Real-time sector metrics (New Highs / New Lows / ADR%) streamed to your dashboard.

Quick start

cp .env.example .env
# put your Polygon key in .env

npm install
npm start

REST

• GET /api/health
• GET /api/market-metrics

WebSocket

• Connect to ws://localhost:5055 and listen for { type: "metrics", payload }

Config

• TIMEFRAME_SEC (default 300 = 5m) affects recompute cadence.
• LOOKBACK_DAYS default 20 for NH/NL and ADR windows.
• Edit data/sectors.json to change sector constituents.

Notes

• Uses Polygon aggregate (A.*) WS to update today’s daily bars on the fly.
• Nightly job refreshes historical baselines.
• Optional Redis cache if you set REDIS_URL.