WebSocket Market Data

import { io } from 'socket.io-client';

const socket = io('https://api.paperinvest.io/v1/ws/market', {
  path: '/socket.io',
  transports: ['websocket'],
  auth: { token: 'Bearer YOUR_JWT' },
});

socket.on('connected', (info) => {
  console.log('Connected:', info);
  socket.emit('subscribe', { symbols: ['AAPL','MSFT','NVDA'], channels: ['quote'] });
});

socket.on('quote', (q) => {
  console.log('Quote:', q.symbol, 'bid', q.bid, 'ask', q.ask);
});

socket.on('error', (err) => {
  console.error('WS error:', err);
});

const es = new EventSource('https://api.paperinvest.io/v1/stream/portfolio/PORTFOLIO_ID', {
  withCredentials: false
});

es.onmessage = (evt) => {
  const snapshot = JSON.parse(evt.data);
  console.log('Equity:', snapshot.totalEquity, 'BP:', snapshot.buyingPower?.dayTrade);
};

es.onerror = (e) => {
  console.error('SSE error', e);
  es.close();
};