​
Step by step

1

Requesting a quote or routes

const getQuote = async (fromChain, toChain, fromToken, toToken, fromAmount, fromAddress) => {
    const result = await axios.get('https://li.quest/v1/quote', {
        params: {
            fromChain,
            toChain,
            fromToken,
            toToken,
            fromAmount,
            fromAddress,
        }
    });
    return result.data;
}

const fromChain = 'DAI';
const fromToken = 'USDC';
const toChain = 'POL';
const toToken = 'USDC';
const fromAmount = '1000000';
const fromAddress = YOUR_WALLET_ADDRESS;

const quote = await getQuote(fromChain, toChain, fromToken, toToken, fromAmount, fromAddress);
2

Choose the desired route if `/routes` was used and retrieve transaction data from `/advanced/stepTransaction`

This step is only needed if /routes endpoint was used. /quote already returns the transaction data within the response. Difference between /quote and /routes is desribed here

3

Setting the allowance

Before any transaction can be sent, it must be made sure that the user is allowed to send the requested amount from the wallet.

const { Contract } = require('ethers');

const ERC20_ABI = [
    {
        "name": "approve",
        "inputs": [
            {
                "internalType": "address",
                "name": "spender",
                "type": "address"
            },
            {
                "internalType": "uint256",
                "name": "amount",
                "type": "uint256"
            }
        ],
        "outputs": [
            {
                "internalType": "bool",
                "name": "",
                "type": "bool"
            }
        ],
        "stateMutability": "nonpayable",
        "type": "function"
    },
    {
        "name": "allowance",
        "inputs": [
            {
                "internalType": "address",
                "name": "owner",
                "type": "address"
            },
            {
                "internalType": "address",
                "name": "spender",
                "type": "address"
            }
        ],
        "outputs": [
            {
                "internalType": "uint256",
                "name": "",
                "type": "uint256"
            }
        ],
        "stateMutability": "view",
        "type": "function"
    }
];

// Get the current allowance and update it if needed
const checkAndSetAllowance = async (wallet, tokenAddress, approvalAddress, amount) => {
    // Transactions with the native token don't need approval
    if (tokenAddress === ethers.constants.AddressZero) {
        return
    }

    const erc20 = new Contract(tokenAddress, ERC20_ABI, wallet);
    const allowance = await erc20.allowance(await wallet.getAddress(), approvalAddress);

    if (allowance.lt(amount)) {
        const approveTx = await erc20.approve(approvalAddress, amount);
        await approveTx.wait();
    }
}

await checkAndSetAllowance(wallet, quote.action.fromToken.address, quote.estimate.approvalAddress, fromAmount);
4

Sending the transaction

After receiving a quote, the transaction has to be sent to trigger the transfer.

Firstly, the wallet has to be configured. The following example connects your wallet to the Gnosis Chain.

const provider = new ethers.providers.JsonRpcProvider('https://rpc.xdaichain.com/', 100);
const wallet = ethers.Wallet.fromMnemonic(YOUR_PERSONAL_MNEMONIC).connect(
    provider
);

Afterward, the transaction can be sent using the transactionRequest inside the previously retrieved quote:

const tx = await wallet.sendTransaction(quote.transactionRequest);
await tx.wait();
5

Executing second step if applicable

If two-step route was used, the second step has to be executed after the first step is complete. Fetch the status of the first step like described in next step and then request transactionData from /advanced/stepTransaction endpoint.

6

Fetching the transfer status

To check if the token was successfully sent to the receiving chain, the /status endpoint can be called:

const getStatus = async (bridge, fromChain, toChain, txHash) => {
    const result = await axios.get('https://li.quest/v1/status', {
        params: {
            bridge,
            fromChain,
            toChain,
            txHash,
        }
    });
    return result.data;
}

result = await getStatus(quote.tool, fromChain, toChain, tx.hash);

​
Full example

const ethers = require('ethers');
const axios = require('axios');

const API_URL = 'https://li.quest/v1';

// Get a quote for your desired transfer
const getQuote = async (fromChain, toChain, fromToken, toToken, fromAmount, fromAddress) => {
    const result = await axios.get(`${API_URL}/quote`, {
        params: {
            fromChain,
            toChain,
            fromToken,
            toToken,
            fromAmount,
            fromAddress,
        }
    });
    return result.data;
}

// Check the status of your transfer
const getStatus = async (bridge, fromChain, toChain, txHash) => {
    const result = await axios.get(`${API_URL}/status`, {
        params: {
            bridge,
            fromChain,
            toChain,
            txHash,
        }
    });
    return result.data;
}

const fromChain = 'DAI';
const fromToken = 'USDC';
const toChain = 'POL';
const toToken = 'USDC';
const fromAmount = '1000000';
const fromAddress = YOUR_WALLET_ADDRESS;

// Set up your wallet
const provider = new ethers.providers.JsonRpcProvider('https://rpc.xdaichain.com/', 100);
const wallet = ethers.Wallet.fromMnemonic(YOUR_PERSONAL_MNEMONIC).connect(
    provider
);

const run = async () => {
    const quote = await getQuote(fromChain, toChain, fromToken, toToken, fromAmount, fromAddress);
    const tx = await wallet.sendTransaction(quote.transactionRequest);

    await tx.wait();

    // Only needed for cross chain transfers
    if (fromChain !== toChain) {
        let result;
        do {
            result = await getStatus(quote.tool, fromChain, toChain, tx.hash);
        } while (result.status !== 'DONE' && result.status !== 'FAILED')
    }
}

run().then(() => {
    console.log('DONE!')
});