coinbase-at-api

A lightweight, event-driven Node.js SDK for Coinbase Advanced Trade API with paper trading and real-time balance tracking.


Features

- 🔐 JWT Authentication (ES256) for Coinbase Advanced Trade API
- 📡 Real-time WebSocket market data (public feed)
- 💰 Live Balance Tracking via private WebSocket + REST polling
- 📊 Paper Trading Engine with configurable fees, slippage, and P&L tracking
- 🚀 Event-Driven Architecture for building trading bots
- 🛡️ Production-ready and battle-tested

Installation

``bash
npm install coinbase-at-api
`

Quick Start

$3

`javascript
import { CoinbaseAT } from 'coinbase-at-api';

const bot = new CoinbaseAT({
apiKey: process.env.COINBASE_API_KEY,
privateKey: process.env.COINBASE_API_SECRET,
mode: 'paper',
paper: {
startingCash: 10000,
feeBps: 60,
slippageBps: 5
}
});

bot.ws.connect();
bot.ws.on('open', () => bot.ws.subscribe(['BTC-USD']));

bot.ws.on('ticker', async (data) => {
console.log(${data.product_id}: $${data.price});
if (parseFloat(data.price) < 95000) {
await bot.orders.marketBuy('BTC-USD', { quoteSize: 1000 });
}
});

bot.paper.on('fill', (order) => {
console.log(Filled: ${order.side} ${order.amount} @ $${order.price});
});

bot.paper.on('pnl', (snap) => {
console.log(Equity: $${snap.equity.toFixed(2)} | P&L: ${snap.returnPct.toFixed(2)}%);
});
`

$3

`javascript
import { CoinbaseAT } from 'coinbase-at-api';

const bot = new CoinbaseAT({
apiKey: process.env.COINBASE_API_KEY,
privateKey: process.env.COINBASE_API_SECRET,
mode: 'live'
});

await bot.initialize();

bot.balances.on('balances', (balances) => {
console.log('Balances:', balances);
});

const accounts = await bot.rest.getAccounts();
console.log(accounts);
`

Configuration

$3

`javascript
new CoinbaseAT({
apiKey: string, // Required: Your Coinbase API key
privateKey: string, // Required: Your EC private key (PEM format)
mode: 'paper' | 'live', // Default: 'paper'
paper: {
startingCash: number, // Default: 10000
feeBps: number, // Default: 60 (0.6%)
slippageBps: number // Default: 5 (0.05%)
}
})
`

API Reference

$3

`javascript
bot.ws.connect() // Connect to public feed
bot.ws.subscribe(['BTC-USD']) // Subscribe to products
bot.ws.on('ticker', (data) => {}) // Listen to price updates
bot.ws.close() // Close connection
`

$3

`javascript
// Market Buy
await bot.orders.marketBuy('BTC-USD', { quoteSize: 1000 })
await bot.orders.marketBuy('BTC-USD', { baseSize: 0.01 })

// Market Sell
await bot.orders.marketSell('BTC-USD', { baseSize: 0.01 })

// Get portfolio
const portfolio = bot.paper.getPortfolio()
// Returns: { cash, positions, lastPrices }
`

$3

`javascript
bot.paper.on('fill', (order) => {
// order: { side, product_id, amount, price, fee, timestamp }
})

bot.paper.on('pnl', (snapshot) => {
// snapshot: { cash, positions, unrealizedValue, equity, totalPnL, returnPct }
})
`

$3

`javascript
await bot.initialize() // Must call first in live mode

bot.balances.on('balances', (balances) => {
// balances: { USD: { available, hold, uuid }, BTC: {...}, ... }
})

bot.balances.on('balance_update', (event) => {
// Real-time WebSocket updates
})

await bot.balances.refreshBalances()
const usdBalance = bot.balances.getBalance('USD')
`

$3

`javascript
const accounts = await bot.rest.getAccounts()
const product = await bot.rest.getProduct('BTC-USD')
const orders = await bot.rest.getOrders()
await bot.rest.cancelOrder(orderId)
`

Environment Variables

Create a .env file:

`bash
COINBASE_API_KEY=organizations/YOUR_ORG/apiKeys/YOUR_KEY_ID
COINBASE_API_SECRET="-----BEGIN EC PRIVATE KEY-----\nYOUR_PRIVATE_KEY\n-----END EC PRIVATE KEY-----"
`

Architecture

`
coinbase-at-api/
├── src/
│ ├── index.js # Main entry point
│ ├── balanceManager.js # Real-time balance tracking
│ ├── client/
│ │ ├── auth.js # JWT signer (ES256)
│ │ ├── rest.js # REST API client
│ │ ├── ws.js # Public WebSocket
│ │ └── wsPrivate.js # Private WebSocket
│ └── brokers/
│ ├── paper.js # Paper trading engine
│ └── live.js # Live trading
├── .env # Your API credentials
└── package.json
`

Security Best Practices

1. Never commit .env` to version control
2. Use API keys with minimal permissions
3. Rotate keys regularly if exposed
4. Test with paper trading first before going live
5. Store private keys securely in environment variables

Roadmap

- Live order execution (LiveBroker)
- Limit orders support
- Stop-loss / take-profit helpers
- Backtesting engine
- TypeScript definitions
- More exchange integrations

Disclaimer

This software is for educational purposes only. Trading cryptocurrencies involves substantial risk of loss. The authors are not responsible for any financial losses incurred while using this library.

Always test with paper trading before using real funds.

License

MIT © 2026 Zephirex Technologies LLC

Support

- Issues: GitHub Issues
- Discussions: GitHub Discussions

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Built with ❤️ for algorithmic traders