Crypto Exchange SDK JavaScript: Engineering Production-Ready Integrations in 2026

The REST client builds headers, query strings, and bodies for Node.js. It also aligns your clock with the exchange so you do not get recv-window or "request expired" errors.

Constructor fields are not shared across packages. Binance uses api_key and api_secret. Bybit V5 uses key and secret. OKX and Bitget also need apiPass. If you pass apiKey into RestClientV5, it will not work.

Public calls need no credentials:

import { MainClient } from "binance";
import { RestClientV5 } from "bybit-api";

const binance = new MainClient();
const bybit = new RestClientV5();

const btcTicker = await binance.get24hrChangeStatistics({ symbol: "BTCUSDT" });
const linearTickers = await bybit.getTickers({ category: "linear" });

Private calls take keys from the environment, not from source:

import { RestClientV5 } from "bybit-api";

const client = new RestClientV5({
  key: process.env.API_KEY_COM,
  secret: process.env.API_SECRET_COM,
  // testnet: true,
});

const positions = await client.getPositionInfo({
  category: "linear",
  symbol: "BTCUSDT",
});

okx-api unwraps a successful body down to data. If the HTTP status is bad, or OKX returns a non-zero code, the SDK throws the full payload so you still see the native error code. That is how you debug "insufficient margin" instead of a generic wrapper error.

None of these clients implement rate limiting. Track weights or request counts yourself.

Reliable real-time data needs persistence, heartbeats, and resubscribe after a drop. The WebSocket clients do that. Public market streams and private account streams are separate. Private ones authenticate automatically when you pass keys.

Event-driven update / message handlers are the default for market data. Order placement is a different path. On venues that expose a WebSocket API, WebsocketAPIClient lets you await the matching reply. That is a first-class feature on bitget-api V3/UTA, and also on binance, bybit-api, okx-api, gateio-api, kucoin-api, @siebly/kraken-api, and @siebly/htx-api. It is not available on coinbase-api or bitmart-api. Those two give you REST plus market/account streams.

When an exchange changes a response field, a unified wrapper can fail quietly or return a half-filled object. These SDKs already ship TypeScript types that match the server. You do not invent those interfaces. You use them. Post-only, reduce-only, and similar flags stay named the way the venue names them.

It is usually cheaper to keep two clean clients, for example okx-api and @siebly/kraken-api, than to debug one abstraction that lies about both.

OKX also has regional hosts. Default is Global (www.okx.com). Set market: 'EEA' for my.okx.com, or market: 'US' for app.okx.com.

Do not treat every venue as HMAC SHA256 plus a timestamp. The SDKs hide the differences, but the differences are real:

• Most venues sign with HMAC. The SDK puts the signature in headers or query params, depending on the exchange. Binance is not "headers only".
• Binance supports HMAC, RSA, and Ed25519. For the WebSocket API, Ed25519 can log in once. HMAC and RSA sign every command.
• Bitget supports HMAC and RSA. Private REST and WS also need apiPass.
• Bybit V5 uses X-BAPI-API-KEY, X-BAPI-SIGN, X-BAPI-TIMESTAMP, and X-BAPI-RECV-WINDOW. That is not the Binance X-MBX-APIKEY plus query-signature model.
• Coinbase Advanced Trade uses ECDSA or Ed25519 keys and JWT. There is no HMAC path in coinbase-api.
• OKX and Bitget need the passphrase (apiPass) in addition to key and secret.

Keep keys in environment variables or a secret manager. The SDKs will not throttle you. That part is still yours.

WebsocketAPIClient wraps sendWSAPIRequest(). Each call gets a request id. When the matching reply arrives, the promise resolves. You do not keep a manual id map in your main loop.

Bybit V5, taken from the SDK examples:

import { WebsocketAPIClient } from "bybit-api";

const wsClient = new WebsocketAPIClient({
  key: process.env.API_KEY_COM,
  secret: process.env.API_SECRET_COM,
  // testnet: true,
});

const order = await wsClient.submitNewOrder({
  category: "linear",
  symbol: "BTCUSDT",
  orderType: "Limit",
  qty: "0.001",
  side: "Buy",
  price: "50000",
});

Bitget's version is V3/UTA only. You need UTA keys, plus the passphrase, and you pass the product group as the first argument:

import { WebsocketAPIClient } from "bitget-api";

const wsClient = new WebsocketAPIClient({
  apiKey: process.env.API_KEY_COM,
  apiSecret: process.env.API_SECRET_COM,
  apiPass: process.env.API_PASS_COM,
  // demoTrading: true,
});

await wsClient.getWSClient().connectWSAPI();

const order = await wsClient.submitNewOrder("spot", {
  orderType: "limit",
  price: "100",
  qty: "0.1",
  side: "buy",
  symbol: "BTCUSDT",
  timeInForce: "gtc",
});

OKX looks the same from the call site (submitNewOrder), but credentials go in an accounts array and the instrument id is BTC-USDT, not BTCUSDT.

Two caveats that the examples actually document:

• Binance WebSocket API is fastest with Ed25519 keys. HMAC and RSA sign every command.
• Bybit demo trading is for consuming events. As of the current SDK notes, it does not support the WebSocket API. Use testnet or live for WebsocketAPIClient.

You still own rate limits on the socket path.

Exchanges drop idle sockets. The clients send ping/pong and reconnect with resubscribe when the heartbeat fails. You still need backoff and a REST resync after a long outage or a maintenance window. See Reliable Crypto WebSocket Client for the surrounding pattern.

Cap order size and daily loss in your process, before the request leaves the box. Use least-privilege keys: no withdrawals, IP-restricted. Checklist: Defining Safety Boundaries for Trading System Prototypes.

Do not assume every venue uses Binance-style request weights.

Binance scores endpoints by weight. A 429 means you are over the window. Keep hitting it and Binance can return 418 and ban the IP for a while. That 418 behavior is a Binance thing, not an OKX or KuCoin thing.

okx-api and kucoin-api mostly document per-endpoint request frequency (N calls per second or per 2 seconds). Track those counters. Back off on 429, then resume. Start from the crypto exchange sdk javascript libraries.

Exchange docs are huge and inconsistent, which wastes context in coding agents. These packages give typed methods and predictable events so generated code is less invented. Siebly AI Prompt Frameworks are there if you want that workflow.

Install only what you need:

npm install binance
npm install bybit-api
npm install okx-api

Other package names, exactly as published:

npm install bitget-api gateio-api kucoin-api coinbase-api bitmart-api
npm install @siebly/kraken-api @siebly/htx-api

Yarn works the same way. Each repo has REST and WebSocket examples. Public market data needs no keys. Private REST and WebsocketAPIClient need keys in env vars. Full index: Siebly SDK Documentation.

Use a dedicated package for the venue you trade, not a unified wrapper that drops fields. Siebly.io publishes a crypto exchange sdk javascript suite with one package per exchange. You get signing, typed requests, and sockets, plus the native order flags that generic libraries flatten away.

Do not hand-roll it. The SDKs sign for you, and the scheme is not the same everywhere. Many venues use HMAC. Binance and Bitget also accept RSA. Binance WebSocket API prefers Ed25519 if you care about login-once latency. Coinbase uses ECDSA or Ed25519 JWT. OKX and Bitget also need a passphrase. Put keys in env vars and let the client attach the signature in whatever form that venue expects.

No. There is no built-in throttle. That is intentional. Implement your own window or leaky bucket, and track the limit model the venue actually publishes. Binance uses weights. OKX and KuCoin mostly use per-endpoint request counts. Your job is to stay under those numbers so you do not collect 429s.

WebsocketAPIClient sends a command on an open socket and returns a promise for that command's reply. You place an order with await, same as REST, without opening a new HTTP connection. The SDK maps the request id. This exists on Binance, Bybit, OKX, Bitget V3/UTA, Gate, KuCoin, Kraken, and HTX. Coinbase and BitMart SDKs do not have this client. They still do REST and stream subscriptions.

Yes. All of them are written in TypeScript and publish types. They run on Node.js. Several also ship a webpack/browser build for public data. Keep private keys off the frontend.

Environment variables or a secret manager. Never commit keys. Disable withdrawals. Restrict IPs. In a crypto exchange sdk javascript setup, pass those values into the client constructor and keep the rest of the app free of secrets.

These npm packages:

• binance for Binance Spot, margin, USD-M, COIN-M, and portfolio margin
• bybit-api for Bybit V5
• okx-api for OKX Global, EEA, and US
• bitget-api for Bitget V2 and V3/UTA
• gateio-api for Gate.com
• kucoin-api for KuCoin Spot, Futures, and Broker
• coinbase-api for Advanced Trade, App, Exchange, International, Prime, and Commerce
• bitmart-api for BitMart Spot and Futures V2
• @siebly/kraken-api for Kraken Spot, derivatives, institutional, and partner APIs
• @siebly/htx-api for HTX Spot and derivatives

Each one is a REST plus WebSocket client for that venue. New packages show up on siebly.io/sdk.

Unified libraries flatten responses and drop flags. Specialized SDKs keep native order types, margin modes, and error codes. When the venue ships a new API version, you update one package instead of waiting for a mapper. That is the whole reason these clients exist.