Swap Crypto

This guide demonstrates how to perform token swaps and cross-chain swaps using the Notus API. You will learn how to retrieve swap quotes, execute swaps, and cross-swaps.

1. Initialize Wallet AccountCopied!

Use your private key to initialize a wallet account. This will allow you to sign messages and interact with the blockchain.

import { privateKeyToAccount } from 'viem/accounts'

const BRZ_POLYGON = '0x4eD141110F6EeeAbA9A1df36d8c26f684d2475Dc'
const USDC_POLYGON = '0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359'
const USDC_ARB = "0xaf88d065e77c8cc2239327c5edb3a432268e5831";


const privKey = '0x<private-key>'
const account = privateKeyToAccount(privKey)

2. Get Smart Wallet AddressCopied!

Before transferring tokens, you need to register and retrieve the smart wallet address for Account Abstraction.

import { useState } from "react";

export default function App() {
  const [accountAbstraction, setAccountAbstraction] = useState("");

  const getSmartWalletAddress = async () => {
    const FACTORY_ADDRESS = "0x0000000000400CdFef5E2714E63d8040b700BC24";
    let res = await fetch(`https://<baseUrl>/api/v1/wallets/register`, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        "x-api-key": "<api-key>",
      },
      body: JSON.stringify({
        externallyOwnedAccount: externallyOwnedAccount,
        factory: FACTORY_ADDRESS,
        salt: "0",
      }),
    });

    if (!res?.ok) {
      return
    }

    const data = await res.json();
    setAccountAbstraction(data.wallet.accountAbstraction);
  };
};

3. Generate a Swap QuoteCopied!

Query a swap quote for token swaps on the same chain (e.g., USDC to BRZ on Polygon).

const swapParams = {
  payGasFeeToken: USDC_POLYGON,
  tokenIn: USDC_POLYGON,
  tokenOut: BRZ_POLYGON,
  amountIn: "5",
  walletAddress: accountAbstraction,
  toAddress: accountAbstraction,
  signerAddress: externallyOwnedAccount,
  chainIdIn: 137,
  chainIdOut: 137,
  gasFeePaymentMethod: "DEDUCT_FROM_AMOUNT",
};

const { data } = await fetch('http://<baseUrl>/api/v1/crypto/swap', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'x-api-key': '<api-key>',
  },
  body: JSON.stringify(swapParams),
}).then((res) => res.json())

If you are swapping from a native token (e.g., ETH, BNB, AVAX), use the following address as tokenIn: 0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee. This ensures that the Notus API recognizes the asset as a native token.

4.Generate a Cross-Swap QuoteCopied!

Query a quote for cross-chain swaps (e.g., USDC on Arbitrum to USDC on Polygon).

const swapParams = {
  payGasFeeToken: USDC_ARB,
  tokenIn: USDC_ARB,
  tokenOut: USDC_POLYGON,
  amountIn: "5",
  walletAddress: accountAbstraction,
  toAddress: accountAbstraction,
  signerAddress: externallyOwnedAccount,
  chainIdIn: 42161,
  chainIdOut: 137,
  gasFeePaymentMethod: "DEDUCT_FROM_AMOUNT",
};

const { data } = await fetch('http://<baseUrl>/api/v1/crypto/cross-swap', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'x-api-key': '<api-key>',
  },
  body: JSON.stringify(crossSwap),
}).then((res) => res.json())

For cross-chain swaps involving a native token, use the following address as tokenIn: 0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee. This ensures that the Notus API recognizes the asset as a native token.

5.Execute Swap or Cross-SwapCopied!

Once you have a quote, sign and execute the swap or cross-swap operation.

const signature = await account.signMessage({
  message: {
    raw: data.quoteId,
  },
})

const res = await fetch('http://<baseUrl>/api/v1/crypto/execute-user-op', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'x-api-key': '<api-key>',
  },
  body: JSON.stringify({ signature, quoteId: data.quoteId }),
}).then((res) => res.json())