O2 SDK for TypeScript

The official TypeScript SDK for the O2 Exchange — a fully on-chain central limit order book (CLOB) DEX on the Fuel Network.

This SDK provides everything you need to trade programmatically on the O2 Exchange: wallet management, account lifecycle, session-based trading, market data retrieval, and real-time WebSocket streaming.

For general information about the O2 Exchange platform, see the O2 Exchange documentation.

Features

• Wallet management — Generate or load Fuel-native and EVM-compatible wallets
• Account lifecycle — Idempotent account setup with automatic faucet and whitelist
• Session-based trading — Delegated signing with automatic nonce management
• Market data — Depth, trades, candles, and ticker data
• Real-time streaming — WebSocket streams via AsyncGenerator / for await
• Full type safety — Branded hex types, bigint chain integers, discriminated action union
• Dual-mode numerics — Pass human-readable strings ("0.02") or raw bigint chain values
• Automatic encoding — Prices and quantities auto-scaled, FractionalPrice adjusted, min_order validated
• Error handling — Typed error classes for every API error code, SessionActionsResponse.success getter

Quick Example

import { O2Client, Network } from "@o2exchange/sdk";

const client = new O2Client({ network: Network.TESTNET });
const wallet = O2Client.generateWallet();
await client.setupAccount(wallet);
await client.createSession(wallet, ["fFUEL/fUSDC"]);
const response = await client.createOrder("fFUEL/fUSDC", "buy", "0.02", "50");
if (response.success) {
  console.log(`Order TX: ${response.txId}`);
}
client.close();
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Installation

npm install @o2exchange/sdk
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Requires Node.js 22.4+. Also works in Bun and modern browsers.

Documentation

• Quick Start — Step-by-step guide to your first trade
• Trading Guide — Order types, batch actions, and advanced patterns
• Market Data — Fetching depth, trades, candles, and tickers
• WebSocket Streams — Real-time data with for await
• Error Handling — Error types and recovery patterns
• Identifiers — Fuel vs EVM wallet choice and owner ID mapping
• External Signers — KMS/HSM integration for production deployments
• API Reference — Full type and method documentation (auto-generated below)