Build with Fusion

Quickstart

The fastest way to integrate Fusion — via the upcoming SDK.

What integration will look like

When the SDK lands, submitting a testnet swap from Arbitrum Sepolia to Base Sepolia will look like this:

import { createFusionClient } from '@fusion-protocol/sdk';

const fusion = createFusionClient({ apiUrl: process.env.FUSION_API_URL });

const { intentId } = await fusion.signAndSubmit(walletClient, {
  fromChain: 421614,
  toChain: 84532,
  fromToken,
  toToken,
  amount,
  minAmountOut,
  recipient,
});

for await (const update of fusion.watchIntent(intentId)) {
  console.log(update.status);
  if (update.status === 'completed' || update.status === 'failed') break;
}

The same pipeline that currently takes ~80 lines of REST, Socket.IO, and typed-data plumbing collapses to a few idiomatic calls.

What the SDK will cover

Core client — getNonce, getSigningDomain, submitIntent, getIntent
signAndSubmit(walletClient, intent) — fetch nonce, fetch domain, sign EIP-712 typed data, and submit in one call
watchIntent(intentId) — a typed Socket.IO wrapper that yields status transitions as an async iterable
React add-on (@fusion-protocol/sdk/react) — a useFusionSwap() hook returning { submit, status, txHashes, error } for drop-in integration into apps
Permit2 helpers — for gasless ERC20 source locks on EVM
Cross-family helpers — for non-EVM source-lock session flows

While you wait

The underlying REST and Socket.IO surfaces are stable and documented. If you need to start building before the SDK ships, the endpoint-level references below are the integration surface the SDK itself will wrap:

API and WebSocket Overview — every current REST endpoint and Socket.IO event
Intent Schema — the signing payload, EIP-712 struct, and address rules per chain family
Wallet App Integration — wallet-side patterns for EVM wallets, non-EVM wallets, and cross-family routes

Anything you hand-roll against those surfaces today will map one-to-one onto the SDK once it lands.