CCXT for TypeScript/JavaScript

A comprehensive guide to using CCXT in TypeScript and JavaScript projects for cryptocurrency exchange integration.

Installation

REST API (Standard CCXT)

npm install ccxt

WebSocket API (Real-time, ccxt.pro)

npm install ccxt

Both REST and WebSocket APIs are included in the same package.

Quick Start

REST API - TypeScript

import ccxt from 'ccxt'

const exchange = new ccxt.binance()
await exchange.loadMarkets()
const ticker = await exchange.fetchTicker('BTC/USDT')
console.log(ticker)

REST API - JavaScript (CommonJS)

const ccxt = require('ccxt')

(async () => {
    const exchange = new ccxt.binance()
    await exchange.loadMarkets()
    const ticker = await exchange.fetchTicker('BTC/USDT')
    console.log(ticker)
})()

WebSocket API - Real-time Updates

import ccxt from 'ccxt'

const exchange = new ccxt.pro.binance()
while (true) {
    const ticker = await exchange.watchTicker('BTC/USDT')
    console.log(ticker)  // Live updates!
}
await exchange.close()

REST vs WebSocket

When to use REST:

• Placing orders
• Fetching account balance
• One-time data queries
• Order management (cancel, fetch orders)

When to use WebSocket:

• Real-time price monitoring
• Live orderbook updates
• Arbitrage detection
• Portfolio tracking with live updates

Creating Exchange Instance

REST API

// Public API (no authentication)
const exchange = new ccxt.binance({
    enableRateLimit: true  // Recommended!
})

// Private API (with authentication)
const exchange = new ccxt.binance({
    apiKey: 'YOUR_API_KEY',
    secret: 'YOUR_SECRET',
    enableRateLimit: true
})

WebSocket API

// Public WebSocket
const exchange = new ccxt.pro.binance()

// Private WebSocket (with authentication)
const exchange = new ccxt.pro.binance({
    apiKey: 'YOUR_API_KEY',
    secret: 'YOUR_SECRET'
})

// Always close when done
await exchange.close()

Common REST Operations

Loading Markets

// Load all available trading pairs
await exchange.loadMarkets()

// Access market information
const btcMarket = exchange.market('BTC/USDT')
console.log(btcMarket.limits.amount.min)  // Minimum order amount

Fetching Ticker

// Single ticker
const ticker = await exchange.fetchTicker('BTC/USDT')
console.log(ticker.last)      // Last price
console.log(ticker.bid)       // Best bid
console.log(ticker.ask)       // Best ask
console.log(ticker.volume)    // 24h volume

// Multiple tickers (if supported)
const tickers = await exchange.fetchTickers(['BTC/USDT', 'ETH/USDT'])

Fetching Order Book

// Full orderbook
const orderbook = await exchange.fetchOrderBook('BTC/USDT')
console.log(orderbook.bids[0])  // [price, amount]
console.log(orderbook.asks[0])  // [price, amount]

// Limited depth
const orderbook = await exchange.fetchOrderBook('BTC/USDT', 5)  // Top 5 levels

Creating Orders

Limit Order

// Buy limit order
const order = await exchange.createLimitBuyOrder('BTC/USDT', 0.01, 50000)
console.log(order.id)

// Sell limit order
const order = await exchange.createLimitSellOrder('BTC/USDT', 0.01, 60000)

// Generic limit order
const order = await exchange.createOrder('BTC/USDT', 'limit', 'buy', 0.01, 50000)

Market Order

// Buy market order
const order = await exchange.createMarketBuyOrder('BTC/USDT', 0.01)

// Sell market order
const order = await exchange.createMarketSellOrder('BTC/USDT', 0.01)

// Generic market order
const order = await exchange.createOrder('BTC/USDT', 'market', 'sell', 0.01)

Fetching Balance

const balance = await exchange.fetchBalance()
console.log(balance.BTC.free)   // Available balance
console.log(balance.BTC.used)   // Balance in orders
console.log(balance.BTC.total)  // Total balance

Fetching Orders

// Open orders
const openOrders = await exchange.fetchOpenOrders('BTC/USDT')

// Closed orders
const closedOrders = await exchange.fetchClosedOrders('BTC/USDT')

// All orders (open + closed)
const allOrders = await exchange.fetchOrders('BTC/USDT')

// Single order by ID
const order = await exchange.fetchOrder(orderId, 'BTC/USDT')

Fetching Trades

// Recent public trades
const trades = await exchange.fetchTrades('BTC/USDT', undefined, 10)

// Your trades (requires authentication)
const myTrades = await exchange.fetchMyTrades('BTC/USDT')

Canceling Orders

// Cancel single order
await exchange.cancelOrder(orderId, 'BTC/USDT')

// Cancel all orders for a symbol
await exchange.cancelAllOrders('BTC/USDT')

WebSocket Operations (Real-time)

Watching Ticker (Live Price Updates)

const exchange = new ccxt.pro.binance()

while (true) {
    const ticker = await exchange.watchTicker('BTC/USDT')
    console.log(ticker.last, ticker.timestamp)
}

await exchange.close()

Watching Order Book (Live Depth Updates)

const exchange = new ccxt.pro.binance()

while (true) {
    const orderbook = await exchange.watchOrderBook('BTC/USDT')
    console.log('Best bid:', orderbook.bids[0])
    console.log('Best ask:', orderbook.asks[0])
}

await exchange.close()

Watching Trades (Live Trade Stream)

const exchange = new ccxt.pro.binance()

while (true) {
    const trades = await exchange.watchTrades('BTC/USDT')
    for (const trade of trades) {
        console.log(trade.price, trade.amount, trade.side)
    }
}

await exchange.close()

Watching Your Orders (Live Order Updates)

const exchange = new ccxt.pro.binance({
    apiKey: 'YOUR_API_KEY',
    secret: 'YOUR_SECRET'
})

while (true) {
    const orders = await exchange.watchOrders('BTC/USDT')
    for (const order of orders) {
        console.log(order.id, order.status, order.filled)
    }
}

await exchange.close()

Watching Balance (Live Balance Updates)

const exchange = new ccxt.pro.binance({
    apiKey: 'YOUR_API_KEY',
    secret: 'YOUR_SECRET'
})

while (true) {
    const balance = await exchange.watchBalance()
    console.log('BTC:', balance.BTC)
    console.log('USDT:', balance.USDT)
}

await exchange.close()

Watching Multiple Symbols

const exchange = new ccxt.pro.binance()
const symbols = ['BTC/USDT', 'ETH/USDT', 'SOL/USDT']

while (true) {
    // Watch all symbols concurrently
    const tickers = await exchange.watchTickers(symbols)
    for (const symbol in tickers) {
        console.log(symbol, tickers[symbol].last)
    }
}

await exchange.close()

Complete Method Reference

Market Data Methods

Tickers & Prices

• fetchTicker(symbol) - Fetch ticker for one symbol
• fetchTickers([symbols]) - Fetch multiple tickers at once
• fetchBidsAsks([symbols]) - Fetch best bid/ask for multiple symbols
• fetchLastPrices([symbols]) - Fetch last prices
• fetchMarkPrices([symbols]) - Fetch mark prices (derivatives)

Order Books

• fetchOrderBook(symbol, limit) - Fetch order book
• fetchOrderBooks([symbols]) - Fetch multiple order books
• fetchL2OrderBook(symbol) - Fetch level 2 order book
• fetchL3OrderBook(symbol) - Fetch level 3 order book (if supported)

Trades

• fetchTrades(symbol, since, limit) - Fetch public trades
• fetchMyTrades(symbol, since, limit) - Fetch your trades (auth required)
• fetchOrderTrades(orderId, symbol) - Fetch trades for specific order

OHLCV (Candlesticks)

• fetchOHLCV(symbol, timeframe, since, limit) - Fetch candlestick data
• fetchIndexOHLCV(symbol, timeframe) - Fetch index price OHLCV
• fetchMarkOHLCV(symbol, timeframe) - Fetch mark price OHLCV
• fetchPremiumIndexOHLCV(symbol, timeframe) - Fetch premium index OHLCV

Account & Balance

• fetchBalance() - Fetch account balance (auth required)
• fetchAccounts() - Fetch sub-accounts
• fetchLedger(code, since, limit) - Fetch ledger history
• fetchLedgerEntry(id, code) - Fetch specific ledger entry
• fetchTransactions(code, since, limit) - Fetch transactions
• fetchDeposits(code, since, limit) - Fetch deposit history
• fetchWithdrawals(code, since, limit) - Fetch withdrawal history
• fetchDepositsWithdrawals(code, since, limit) - Fetch both deposits and withdrawals

Trading Methods

Creating Orders

• createOrder(symbol, type, side, amount, price, params) - Create order (generic)
• createLimitOrder(symbol, side, amount, price) - Create limit order
• createMarketOrder(symbol, side, amount) - Create market order
• createLimitBuyOrder(symbol, amount, price) - Buy limit order
• createLimitSellOrder(symbol, amount, price) - Sell limit order
• createMarketBuyOrder(symbol, amount) - Buy market order
• createMarketSellOrder(symbol, amount) - Sell market order
• createMarketBuyOrderWithCost(symbol, cost) - Buy with specific cost
• createStopLimitOrder(symbol, side, amount, price, stopPrice) - Stop-limit order
• createStopMarketOrder(symbol, side, amount, stopPrice) - Stop-market order
• createStopLossOrder(symbol, side, amount, stopPrice) - Stop-loss order
• createTakeProfitOrder(symbol, side, amount, takeProfitPrice) - Take-profit order
• createTrailingAmountOrder(symbol, side, amount, trailingAmount) - Trailing stop
• createTrailingPercentOrder(symbol, side, amount, trailingPercent) - Trailing stop %
• createTriggerOrder(symbol, side, amount, triggerPrice) - Trigger order
• createPostOnlyOrder(symbol, side, amount, price) - Post-only order
• createReduceOnlyOrder(symbol, side, amount, price) - Reduce-only order
• createOrders([orders]) - Create multiple orders at once
• createOrderWithTakeProfitAndStopLoss(symbol, type, side, amount, price, tpPrice, slPrice) - OCO order

Managing Orders

• fetchOrder(orderId, symbol) - Fetch single order
• fetchOrders(symbol, since, limit) - Fetch all orders
• fetchOpenOrders(symbol, since, limit) - Fetch open orders
• fetchClosedOrders(symbol, since, limit) - Fetch closed orders
• fetchCanceledOrders(symbol, since, limit) - Fetch canceled orders
• fetchOpenOrder(orderId, symbol) - Fetch specific open order
• fetchOrdersByStatus(status, symbol) - Fetch orders by status
• cancelOrder(orderId, symbol) - Cancel single order
• cancelOrders([orderIds], symbol) - Cancel multiple orders
• cancelAllOrders(symbol) - Cancel all orders for symbol
• editOrder(orderId, symbol, type, side, amount, price) - Modify order

Margin & Leverage

• fetchBorrowRate(code) - Fetch borrow rate for margin
• fetchBorrowRates([codes]) - Fetch multiple borrow rates
• fetchBorrowRateHistory(code, since, limit) - Historical borrow rates
• fetchCrossBorrowRate(code) - Cross margin borrow rate
• fetchIsolatedBorrowRate(symbol, code) - Isolated margin borrow rate
• borrowMargin(code, amount, symbol) - Borrow margin
• repayMargin(code, amount, symbol) - Repay margin
• fetchLeverage(symbol) - Fetch leverage
• setLeverage(leverage, symbol) - Set leverage
• fetchLeverageTiers(symbols) - Fetch leverage tiers
• fetchMarketLeverageTiers(symbol) - Leverage tiers for market
• setMarginMode(marginMode, symbol) - Set margin mode (cross/isolated)
• fetchMarginMode(symbol) - Fetch margin mode

Derivatives & Futures

Positions

• fetchPosition(symbol) - Fetch single position
• fetchPositions([symbols]) - Fetch all positions
• fetchPositionsForSymbol(symbol) - Fetch positions for symbol
• fetchPositionHistory(symbol, since, limit) - Position history
• fetchPositionsHistory(symbols, since, limit) - Multiple position history
• fetchPositionMode(symbol) - Fetch position mode (one-way/hedge)
• setPositionMode(hedged, symbol) - Set position mode
• closePosition(symbol, side) - Close position
• closeAllPositions() - Close all positions

Funding & Settlement

• fetchFundingRate(symbol) - Current funding rate
• fetchFundingRates([symbols]) - Multiple funding rates
• fetchFundingRateHistory(symbol, since, limit) - Funding rate history
• fetchFundingHistory(symbol, since, limit) - Your funding payments
• fetchFundingInterval(symbol) - Funding interval
• fetchSettlementHistory(symbol, since, limit) - Settlement history
• fetchMySettlementHistory(symbol, since, limit) - Your settlement history

Open Interest & Liquidations

• fetchOpenInterest(symbol) - Open interest for symbol
• fetchOpenInterests([symbols]) - Multiple open interests
• fetchOpenInterestHistory(symbol, timeframe, since, limit) - OI history
• fetchLiquidations(symbol, since, limit) - Public liquidations
• fetchMyLiquidations(symbol, since, limit) - Your liquidations

Options

• fetchOption(symbol) - Fetch option info
• fetchOptionChain(code) - Fetch option chain
• fetchGreeks(symbol) - Fetch option greeks
• fetchVolatilityHistory(code, since, limit) - Volatility history
• fetchUnderlyingAssets() - Fetch underlying assets

Fees & Limits

• fetchTradingFee(symbol) - Trading fee for symbol
• fetchTradingFees([symbols]) - Trading fees for multiple symbols
• fetchTradingLimits([symbols]) - Trading limits
• fetchTransactionFee(code) - Transaction/withdrawal fee
• fetchTransactionFees([codes]) - Multiple transaction fees
• fetchDepositWithdrawFee(code) - Deposit/withdrawal fee
• fetchDepositWithdrawFees([codes]) - Multiple deposit/withdraw fees

Deposits & Withdrawals

• fetchDepositAddress(code, params) - Get deposit address
• fetchDepositAddresses([codes]) - Multiple deposit addresses
• fetchDepositAddressesByNetwork(code) - Addresses by network
• createDepositAddress(code, params) - Create new deposit address
• fetchDeposit(id, code) - Fetch single deposit
• fetchWithdrawal(id, code) - Fetch single withdrawal
• fetchWithdrawAddresses(code) - Fetch withdrawal addresses
• fetchWithdrawalWhitelist(code) - Fetch whitelist
• withdraw(code, amount, address, tag, params) - Withdraw funds
• deposit(code, amount, params) - Deposit funds (if supported)

Transfer & Convert

• transfer(code, amount, fromAccount, toAccount) - Internal transfer
• fetchTransfer(id, code) - Fetch transfer info
• fetchTransfers(code, since, limit) - Fetch transfer history
• fetchConvertCurrencies() - Currencies available for convert
• fetchConvertQuote(fromCode, toCode, amount) - Get conversion quote
• createConvertTrade(fromCode, toCode, amount) - Execute conversion
• fetchConvertTrade(id) - Fetch convert trade
• fetchConvertTradeHistory(code, since, limit) - Convert history

Market Info

• fetchMarkets() - Fetch all markets
• fetchCurrencies() - Fetch all currencies
• fetchTime() - Fetch exchange server time
• fetchStatus() - Fetch exchange status
• fetchBorrowInterest(code, symbol, since, limit) - Borrow interest paid
• fetchLongShortRatio(symbol, timeframe, since, limit) - Long/short ratio
• fetchLongShortRatioHistory(symbol, timeframe, since, limit) - L/S ratio history

WebSocket Methods (ccxt.pro)

All REST methods have WebSocket equivalents with watch* prefix:

Real-time Market Data

• watchTicker(symbol) - Watch single ticker
• watchTickers([symbols]) - Watch multiple tickers
• watchOrderBook(symbol) - Watch order book updates
• watchOrderBookForSymbols([symbols]) - Watch multiple order books
• watchTrades(symbol) - Watch public trades
• watchOHLCV(symbol, timeframe) - Watch candlestick updates
• watchBidsAsks([symbols]) - Watch best bid/ask

Real-time Account Data (Auth Required)

• watchBalance() - Watch balance updates
• watchOrders(symbol) - Watch your order updates
• watchMyTrades(symbol) - Watch your trade updates
• watchPositions([symbols]) - Watch position updates
• watchPositionsForSymbol(symbol) - Watch positions for symbol

Authentication Required

Methods marked with 🔒 require API credentials:

• All create* methods (creating orders, addresses)
• All cancel* methods (canceling orders)
• All edit* methods (modifying orders)
• All fetchMy* methods (your trades, orders)
• fetchBalance, fetchLedger, fetchAccounts
• withdraw, transfer, deposit
• Margin/leverage methods
• Position methods
• watchBalance, watchOrders, watchMyTrades, watchPositions

Checking Method Availability

Not all exchanges support all methods. Check before using:

// Check if method is supported
if (exchange.has['fetchOHLCV']) {
    const candles = await exchange.fetchOHLCV('BTC/USDT', '1h')
}

// Check multiple capabilities
console.log(exchange.has)
// {
//   fetchTicker: true,
//   fetchOHLCV: true,
//   fetchMyTrades: true,
//   fetchPositions: false,
//   ...
// }

Method Naming Convention

• fetch* - REST API methods (HTTP requests)
• watch* - WebSocket methods (real-time streams)
• create* - Create new resources (orders, addresses)
• cancel* - Cancel existing resources
• edit* - Modify existing resources
• set* - Configure settings (leverage, margin mode)
• *Ws suffix - WebSocket variant (some exchanges)

Proxy Configuration

CCXT supports HTTP, HTTPS, and SOCKS proxies for both REST and WebSocket connections.

Setting Proxy

// HTTP Proxy
exchange.httpProxy = 'http://your-proxy-host:port'

// HTTPS Proxy  
exchange.httpsProxy = 'https://your-proxy-host:port'

// SOCKS Proxy
exchange.socksProxy = 'socks://your-proxy-host:port'

// Proxy with authentication
exchange.httpProxy = 'http://user:pass@proxy-host:port'

Proxy for WebSocket

WebSocket connections also respect proxy settings:

exchange.httpsProxy = 'https://proxy:8080'
// WebSocket connections will use this proxy

Testing Proxy Connection

exchange.httpProxy = 'http://localhost:8080'
try {
    await exchange.fetchTicker('BTC/USDT')
    console.log('Proxy working!')
} catch (error) {
    console.error('Proxy connection failed:', error)
}

WebSocket-Specific Methods

Some exchanges provide WebSocket variants of REST methods for faster order placement and management. These use the *Ws suffix:

Trading via WebSocket

Creating Orders:

• createOrderWs - Create order via WebSocket (faster than REST)
• createLimitOrderWs - Create limit order via WebSocket
• createMarketOrderWs - Create market order via WebSocket
• createLimitBuyOrderWs - Buy limit order via WebSocket
• createLimitSellOrderWs - Sell limit order via WebSocket
• createMarketBuyOrderWs - Buy market order via WebSocket
• createMarketSellOrderWs - Sell market order via WebSocket
• createStopLimitOrderWs - Stop-limit order via WebSocket
• createStopMarketOrderWs - Stop-market order via WebSocket
• createStopLossOrderWs - Stop-loss order via WebSocket
• createTakeProfitOrderWs - Take-profit order via WebSocket
• createTrailingAmountOrderWs - Trailing stop via WebSocket
• createTrailingPercentOrderWs - Trailing stop % via WebSocket
• createPostOnlyOrderWs - Post-only order via WebSocket
• createReduceOnlyOrderWs - Reduce-only order via WebSocket

Managing Orders:

• editOrderWs - Edit order via WebSocket
• cancelOrderWs - Cancel order via WebSocket (faster than REST)
• cancelOrdersWs - Cancel multiple orders via WebSocket
• cancelAllOrdersWs - Cancel all orders via WebSocket

Fetching Data:

• fetchOrderWs - Fetch order via WebSocket
• fetchOrdersWs - Fetch orders via WebSocket
• fetchOpenOrdersWs - Fetch open orders via WebSocket
• fetchClosedOrdersWs - Fetch closed orders via WebSocket
• fetchMyTradesWs - Fetch your trades via WebSocket
• fetchBalanceWs - Fetch balance via WebSocket
• fetchPositionWs - Fetch position via WebSocket
• fetchPositionsWs - Fetch positions via WebSocket
• fetchPositionsForSymbolWs - Fetch positions for symbol via WebSocket
• fetchTradingFeesWs - Fetch trading fees via WebSocket

When to Use WebSocket Methods

Use *Ws methods when:

• You need faster order placement (lower latency)
• You're already connected via WebSocket
• You want to reduce REST API rate limit usage
• Trading strategies require sub-100ms latency

Use REST methods when:

• You need guaranteed execution confirmation
• You're making one-off requests
• The exchange doesn't support the WebSocket variant
• You need detailed error responses

Example: Order Placement Comparison

REST API (slower, more reliable):

const order = await exchange.createOrder('BTC/USDT', 'limit', 'buy', 0.01, 50000)

WebSocket API (faster, lower latency):

const order = await exchange.createOrderWs('BTC/USDT', 'limit', 'buy', 0.01, 50000)

Checking WebSocket Method Availability

Not all exchanges support WebSocket trading methods:

if (exchange.has['createOrderWs']) {
    // Exchange supports WebSocket order creation
    const order = await exchange.createOrderWs('BTC/USDT', 'limit', 'buy', 0.01, 50000)
} else {
    // Fall back to REST
    const order = await exchange.createOrder('BTC/USDT', 'limit', 'buy', 0.01, 50000)
}

Authentication

Setting API Keys

// During instantiation
const exchange = new ccxt.binance({
    apiKey: 'YOUR_API_KEY',
    secret: 'YOUR_SECRET',
    enableRateLimit: true
})

// After instantiation
exchange.apiKey = 'YOUR_API_KEY'
exchange.secret = 'YOUR_SECRET'

Environment Variables (Recommended)

const exchange = new ccxt.binance({
    apiKey: process.env.BINANCE_API_KEY,
    secret: process.env.BINANCE_SECRET,
    enableRateLimit: true
})

Testing Authentication

try {
    const balance = await exchange.fetchBalance()
    console.log('Authentication successful!')
} catch (error) {
    if (error instanceof ccxt.AuthenticationError) {
        console.error('Invalid API credentials')
    }
}

Error Handling

Exception Hierarchy

BaseError
├─ NetworkError (recoverable - retry)
│  ├─ RequestTimeout
│  ├─ ExchangeNotAvailable
│  ├─ RateLimitExceeded
│  └─ DDoSProtection
└─ ExchangeError (non-recoverable - don't retry)
   ├─ AuthenticationError
   ├─ InsufficientFunds
   ├─ InvalidOrder
   └─ NotSupported

Basic Error Handling

import ccxt from 'ccxt'

try {
    const ticker = await exchange.fetchTicker('BTC/USDT')
} catch (error) {
    if (error instanceof ccxt.NetworkError) {
        console.error('Network error - retry:', error.message)
    } else if (error instanceof ccxt.ExchangeError) {
        console.error('Exchange error - do not retry:', error.message)
    } else {
        console.error('Unknown error:', error)
    }
}

Specific Exception Handling

try {
    const order = await exchange.createOrder('BTC/USDT', 'limit', 'buy', 0.01, 50000)
} catch (error) {
    if (error instanceof ccxt.InsufficientFunds) {
        console.error('Not enough balance')
    } else if (error instanceof ccxt.InvalidOrder) {
        console.error('Invalid order parameters')
    } else if (error instanceof ccxt.RateLimitExceeded) {
        console.error('Rate limit hit - wait before retrying')
        await exchange.sleep(1000)  // Wait 1 second
    } else if (error instanceof ccxt.AuthenticationError) {
        console.error('Check your API credentials')
    }
}

Retry Logic for Network Errors

async function fetchWithRetry(maxRetries = 3) {
    for (let i = 0; i < maxRetries; i++) {
        try {
            return await exchange.fetchTicker('BTC/USDT')
        } catch (error) {
            if (error instanceof ccxt.NetworkError && i < maxRetries - 1) {
                console.log(`Retry ${i + 1}/${maxRetries}`)
                await exchange.sleep(1000 * (i + 1))  // Exponential backoff
            } else {
                throw error
            }
        }
    }
}

Rate Limiting

Built-in Rate Limiter (Recommended)

const exchange = new ccxt.binance({
    enableRateLimit: true  // Automatically throttles requests
})

Manual Delays

await exchange.fetchTicker('BTC/USDT')
await exchange.sleep(1000)  // Wait 1 second
await exchange.fetchTicker('ETH/USDT')

Checking Rate Limit

console.log(exchange.rateLimit)  // Milliseconds between requests

Common Pitfalls

Forgetting await

// Wrong - returns Promise, not data
const ticker = exchange.fetchTicker('BTC/USDT')
console.log(ticker.last)  // ERROR: ticker is a Promise!

// Correct
const ticker = await exchange.fetchTicker('BTC/USDT')
console.log(ticker.last)  // Works!

Using REST for Real-time Monitoring

// Wrong - wastes rate limits, slow
while (true) {
    const ticker = await exchange.fetchTicker('BTC/USDT')  // REST
    console.log(ticker.last)
    await exchange.sleep(1000)
}

// Correct - use WebSocket
const exchange = new ccxt.pro.binance()
while (true) {
    const ticker = await exchange.watchTicker('BTC/USDT')  // WebSocket
    console.log(ticker.last)
}

Not Closing WebSocket Connections

// Wrong - memory leak
const exchange = new ccxt.pro.binance()
const ticker = await exchange.watchTicker('BTC/USDT')
// Forgot to close!

// Correct
const exchange = new ccxt.pro.binance()
try {
    while (true) {
        const ticker = await exchange.watchTicker('BTC/USDT')
        console.log(ticker)
    }
} finally {
    await exchange.close()
}

Multiple Instances with Same API Keys

// Wrong - nonce conflicts
const ex1 = new ccxt.binance({ apiKey: 'key', secret: 'secret' })
const ex2 = new ccxt.binance({ apiKey: 'key', secret: 'secret' })
await ex1.fetchBalance()
await ex2.fetchBalance()  // May fail due to nonce issues!

// Correct - reuse single instance
const exchange = new ccxt.binance({ apiKey: 'key', secret: 'secret' })
await exchange.fetchBalance()
await exchange.fetchBalance()

Not Enabling Rate Limiter

// Wrong - may hit rate limits
const exchange = new ccxt.binance()
for (let i = 0; i < 100; i++) {
    await exchange.fetchTicker('BTC/USDT')  // May fail!
}

// Correct
const exchange = new ccxt.binance({ enableRateLimit: true })
for (let i = 0; i < 100; i++) {
    await exchange.fetchTicker('BTC/USDT')  // Automatically throttled
}

Browser Usage

Via CDN

<script src="https://cdn.jsdelivr.net/npm/ccxt@latest/dist/ccxt.browser.js"></script>
<script>
    const exchange = new ccxt.binance()
    exchange.loadMarkets().then(() => {
        return exchange.fetchTicker('BTC/USDT')
    }).then(ticker => {
        console.log(ticker)
    })
</script>

ES Modules

import ccxt from 'https://cdn.jsdelivr.net/npm/ccxt@latest/dist/ccxt.browser.js'

const exchange = new ccxt.binance()
await exchange.loadMarkets()
const ticker = await exchange.fetchTicker('BTC/USDT')
console.log(ticker)

Troubleshooting

Common Issues

1. "Cannot find module 'ccxt'"

• Solution: Run npm install ccxt

2. "RateLimitExceeded"

• Solution: Enable rate limiter: enableRateLimit: true
• Or add manual delays between requests

3. "AuthenticationError"

• Solution: Check API key and secret
• Verify API key permissions on exchange
• Check system clock is synced (use NTP)

4. "InvalidNonce"

• Solution: Sync system clock
• Use only one exchange instance per API key
• Don't run multiple bots with same credentials

5. "InsufficientFunds"

• Solution: Check available balance (balance.BTC.free)
• Account for trading fees

6. "ExchangeNotAvailable"

• Solution: Check exchange status/maintenance
• Retry after a delay
• Use different exchange endpoint if available

7. WebSocket connection drops

• Solution: Implement reconnection logic
• Use try-catch and restart watch* methods
• Check network stability

Debugging

// Enable verbose logging
exchange.verbose = true

// Check exchange capabilities
console.log(exchange.has)
// {
//   fetchTicker: true,
//   fetchOrderBook: true,
//   createOrder: true,
//   ...
// }

// Check market information
console.log(exchange.markets['BTC/USDT'])

// Check last request/response
console.log(exchange.last_http_response)
console.log(exchange.last_json_response)

Prediction Markets

CCXT supports prediction-market exchanges (Polymarket, Kalshi, Limitless, Myriad, Hyperliquid) under a dedicated ccxt.prediction namespace. They use the same unified API, but prices are quoted 0–1 (USDC per outcome share) and the tradeable unit is an outcome (e.g. a market's YES/NO token), not a regular market symbol.

import ccxt from 'ccxt';

const exchange = new ccxt.prediction.polymarket ();
await exchange.loadMarkets ();
// discover events → markets → outcomes
const events = await exchange.fetchEvents ({ 'query': 'Trump' });
const outcome = events[0]['markets'][0]['outcomes'][0];
// each outcome has: outcome (the handle, e.g. 'TRUMP_OUT_PRESIDENT_2027:YES'),
// outcomeId, market, label ('YES'/'NO')
const handle = outcome['outcome'];
const ticker = await exchange.fetchTicker (handle);
const book = await exchange.fetchOrderBook (handle);
// limit buy 5 YES shares @ 0.40 USDC (price is 0..1 per share)
const order = await exchange.createOrder (handle, 'limit', 'buy', 5, 0.40);
await exchange.cancelOrder (order['id'], handle);

• Price/trade methods (fetchTicker, fetchOrderBook, fetchOHLCV, fetchTrades, createOrder, cancelOrder, …) take an outcome handle or outcomeId (the outcome / outcomes parameter), not symbol.
• Check support with exchange.has['prediction']; discover markets via fetchEvents / fetchEvent (or loadMarkets).

Order Router

Two things, either usable without the other. A client for the CCXT order-router service — a separate process holding live books across many venues, which answers "what is the cheapest way to turn asset A into asset B right now?", including bridges (SOL -> USDT -> BTC when no SOL/BTC market exists). And an execution engine for plans you build yourself, which needs no router service and no apiKey. It is not an exchange: it does not extend Exchange, has no unified methods, and is constructed directly.

import ccxt from 'ccxt';

const router = new ccxt.OrderRouter ();

//  exactly one of amountIn / amountOut
const route = await router.fetchRoute ('USDT', 'BTC', { 'amountIn': 1000 });
console.log (route['effectiveRate'], route['impactBps'], route['fillRatio']);

//  execute takes the route directly: it builds the plan, loads each venue's markets and
//  runs the safety check itself, refusing to place anything on a blocking violation
const report = await router.execute (route, { 'binance': binance, 'kraken': kraken }, {
    'strategy': 'sequential',
    'usdRates': { 'USDT': 1 },
});
//  want to see or change the plan first? the steps in between are public and PURE (no I/O):
//  buildExecutionPlan (route, {}) then checkExecutionPlanSafety (plan, markets, {})

execute defaults to dry_run, and anything other than an explicit live flag forces dry_run regardless of the strategy requested — a call that looks live but forgot the flag places nothing.

The service, and what it costs

https://docs.ccxt.com/router/api. Every endpoint is public: there is no API key, no signup and no login. The service rate-limits by client IP address instead.

The client still accepts an apiKey and still sends it as x-api-key when you pass one, so a deployment that fronts the service with its own authentication keeps working. With no key the header is omitted entirely rather than sent empty.

The full contract is published as OpenAPI 3.1 at https://docs.ccxt.com/router/openapi.yaml. curl -O https://docs.ccxt.com/router/openapi.yaml and point codegen at it, import it into Postman/Insomnia, or diff it between deploys. It is the authority on every field this client reads; where the two disagree, the spec is right. Rendered prose version: /router/docs and /router/docs/api.

Free to use for now, up to the published rate limit — not a permanent commitment, so expect a paid tier eventually. Your existing key is how that would be billed; nothing in the client changes. Read the limit off the response headers (x-ratelimit-limit, x-ratelimit-remaining, x-ratelimit-reset) rather than hardcoding a number. A 429 raises RateLimitExceeded with the retry interval folded into the message.

A router that has restarted is alive long before it can price anything. Asked to route in that window it refuses with 503 cache_cold, and the client raises ExchangeNotAvailable — a retry, distinct from the ExchangeError that means something is actually wrong.

Holdings are POSTed, never put in a URL. fetchRoute normally sends a GET, but when you pass balances the client switches to POST /route and puts every parameter in the body: the service scrubs holdings from its own logs, but a reverse proxy, an ALB, a CDN, browser history and a Referer all see the full request line, and no in-process redaction reaches them. fetchRouteWithBalances does this for you.

Two flags the client verifies for you, because one silently lost in transit looks identical to one never sent. balances: the service ignores them entirely if it predates the feature and answers byte-identically, so fetchRoute throws unless the router echoes balancesApplied (or balanceEntryCount, which is how an empty wallet is confirmed) — pass requireBalancesApplied: false to opt out. requireFullFill: the one flag that fails open, so the client stamps what you asked for and the safety check makes partial_fill blocking when you asked for a full fill and did not get one.

An empty value is not an omitted one. Omit bridges and you get the default bridge set; send bridges= and you have asked for no bridging at all. Same for exchanges= (no venues) and balances= (you hold nothing). The client forwards an empty value rather than dropping it.

requestId is sent as the x-request-id header, so your log and the router's decision log can be joined; the service mints one when absent.

Asking the service about itself

Gate deploys on readiness, not health — /health is 200 before a single websocket has connected. fetchReadiness () does not raise when the answer is no: the service replies 503 carrying the same body it returns on 200, and you need those counts to know why.

const readiness = await router.fetchReadiness ();
if (readiness['status'] !== 'ready') {
    console.log (readiness['freshCount'], 'of', readiness['bookCount'], 'books are fresh');
}

/metrics (Prometheus) has no client method — it answers text/plain and this class parses every response as JSON.

Watching a route. watchRoute holds a WebSocket open and calls your hook with each RouteResult as the books move; return 'stop' to close cleanly and get the last route back. Every frame is stamped exactly as fetchRoute stamps its answer, so it can go straight into the plan builder. Three endpoint rules differ from fetchRoute: balances and balanceMode are refused (a socket outlives the holdings it was opened with — refused client-side, before anything opens), includeQuotes defaults to false, and refusals arrive as close codes rather than statuses — 1008 raises BadRequest and 1013 raises ExchangeNotAvailable, the same classes the REST path uses. A hook that throws stops the stream and reaches you, unlike execute's step hook.

Watching a run, and stopping it

execute is not opaque. options.onStep is called after each step completes AND after its reconciliation — never mid-order — and its return value decides whether the route continues.

const report = await router.execute (plan, venues, {
    'strategy': 'sequential', 'usdRates': { 'USDT': 1 },
    'retryFailedSteps': 2,               // only a DEFINITIVELY REJECTED step is retried
    'onStep': (event) => {
        console.log (event['stepIndex'], event['status'], event['outAmount']);
        return (event['status'] === 'partial') ? 'halt' : '';   // 'halt' stops the route
    },
});

The event is a plain dictionary: planId, stepIndex, hopIndex, legIndex, exchangeId, symbol, side, status, requestedAmount, filledAmount, outAsset, outAmount, orderId, clientOrderId, errorCode, attempt, reconciliation, ordersPlaced, halted, haltReason, stepsTotal, stepsRemaining.

• It can only narrow. 'halt' stops the route and sets haltReason to halted_by_on_step; nothing it returns resumes a route the reconciliation already halted.
• It is called on the halt paths too, with an empty reconciliation, so it always learns how the route ended.
• Do no network I/O in it — it sits between orders on the money path.
• A hook that throws is recorded in report['errors'] as on_step_hook_failed and the run continues; losing the report would destroy the only account of orders already live.

For decisions that need I/O, slice the plan and call execute per hop with its own idempotencyKey instead.

options.retryFailedSteps (default 0, retryDelayMs default 1000) re-places a step the venue definitively rejected. An outcome_unknown step is never retried at any setting: it may already be a live position, and re-placing it is the double-fill this class exists to prevent. The winning attempt is reported as attempt. The router sets no client order id of its own — venues disagree on length and charset, so whatever you pass in orderParams travels untouched.

Executing your own plans

execute takes a plan, not a route, and never checks where the plan came from — so your own strategy can supply its own trades and still get the notional cap, halt-and-reconcile between hops, resting-order cleanup and the unwind plan. A plan that has been through JSON or a database, or a hand-rebuilt tail of a halted route, is equally valid.

A step is one order on one venue. Required: exchangeId, symbol, side, amount, base, quote. Optional: stepIndex (defaults to position), hopIndex/legIndex (steps sharing a hopIndex are one hop — what parallel_within_hop parallelises), expectedPrice, limitPrice, notionalQuote.

const plan = {
    'requestId': 'my-strategy-0001',            // identity; a live run refuses without one
    'calculatedAt': exchange.milliseconds (),
    'steps': [
        { 'exchangeId': 'binance', 'symbol': 'BTC/USDT', 'side': 'buy', 'amount': 0.01,
          'base': 'BTC', 'quote': 'USDT', 'hopIndex': 0, 'expectedPrice': 64000 },
    ],
};
const report = await router.execute (plan, { 'binance': binance }, {
    'strategy': 'sequential', 'usdRates': { 'USDT': 1 }, 'maxNotionalUsd': 25,
});

A live execute requires an identity and refuses without one: the identity is remembered in-process so a second execute of the same plan is refused before any venue is contacted. Supply it as plan['requestId'] or as options.idempotencyKey. execute never sets a clientOrderId of its own: each exchange's createOrder keeps sending whatever identifier it generates internally, and a clientOrderId you put in options.orderParams travels untouched (to every step alike).

Make it stable and tied to the intent (a strategy name plus the signal's timestamp). A fresh value per call — Date.now() and friends — turns the guard off while looking like it is on. To re-run deliberately, pass options.allowReexecution. The guard does not survive a restart.

checkExecutionPlanSafety is worth running on a hand-written plan first: it checks every step against that venue's real market rules — minimum amount, minimum cost, precision — which is where a hand-picked amount usually goes wrong.

Strategies: dry_run (default), sequential, parallel_within_hop (concurrent across venues, serialised within a venue), limit_protected (rests a limit order and cancels it at orderTimeoutMs, polling every pollIntervalMs), atomic_ish (requires the route pre-funded), best_effort (single-hop, never halts).

Every report carries planAgeMs — how old the plan's prices were when execute was called (-1 when the route carried no calculatedAt, which means unknown, not fresh). Pass options.maxPlanAgeMs to refuse a live execution of a plan older than that; there is no default limit, and under an active limit a plan whose age cannot be determined is refused too.

There is no notional cap by default — trade cents or trade thousands. maxNotionalUsd is an opt-in guardrail: pass it to the constructor, or per call in the options, and it is honoured exactly at whatever value you choose, in either direction; omit it (or pass 0) and no notional check runs. Only a negative value is refused.

A market order cannot be placed under a cap: the cap is checked against the plan's limit price and a market order carries no price at all, so asking for allowMarketOrders together with a cap is refused rather than silently unbounded.

When a cap IS set it is enforced immediately before every order — not just at plan time, because a reconciliation may have resized the plan since — and a step that cannot be valued in USD blocks, so supply a USD rate for every quote asset in the plan. With no cap set there is nothing to evaluate and USD rates are not required either.

In the report, status: 'outcome_unknown' means the request may or may not have reached the venue — execution halts rather than reconciling, because reconciling would read the fill as 0 and report "nothing filled", asserting the one thing nobody knows. Check the open orders and the venue before retrying. placementAttempted is false until an order was actually dispatched.

buildExecutionPlan refuses a route that does not run from the asset you offered to the asset you wanted, or whose hops do not connect — the answer is checked against the client's own record of the question, so a compromised or buggy router response cannot steer orders into another market.

Full reference: Order Router in the CCXT Manual.

Learn More

• CCXT Manual
• CCXT Pro Documentation
• Supported Exchanges
• GitHub Repository