Simple Native ETH Transfer

This is the simplest embedded action — swap tokens crosschain to ETH, then transfer the ETH to a recipient address. Setting isNativeTransfer: true tells the MulticallHandler this is a plain value transfer with no contract function call.

Action Configuration

action.json

{
  "actions": [
    {
      "target": "0xA4d353BBc130cbeF1811f27ac70989F9d568CeAB",
      "functionSignature": "",
      "args": [],
      "value": "0",
      "isNativeTransfer": true,
      "populateCallValueDynamically": true
    }
  ]
}

How It Works

target — The address that receives the ETH
functionSignature — Must be an empty string "" for native transfers
args — Must be an empty array [] for native transfers
isNativeTransfer: true — Signals a simple ETH transfer, not a contract call
populateCallValueDynamically: true — The entire ETH balance from the swap is sent to the target address

When both isNativeTransfer and populateCallValueDynamically are true, the entire ETH balance from the swap is sent directly to the target address. The actual amount is determined at execution time.

Full Example

swap-and-transfer-eth.ts

import { createWalletClient, createPublicClient, http, parseUnits } from "viem";
import { arbitrum } from "viem/chains";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount("0xYOUR_PRIVATE_KEY");

const walletClient = createWalletClient({
  account,
  chain: arbitrum,
  transport: http(),
});

const publicClient = createPublicClient({
  chain: arbitrum,
  transport: http(),
});

const MULTICALL_HANDLER_ETH = "0x924a9f036260DdD5808007E1AA95f08eD08aA569";
const ETH_RECIPIENT = "0xA4d353BBc130cbeF1811f27ac70989F9d568CeAB";

async function swapAndTransferEth() {
  const params = new URLSearchParams({
    tradeType: "exactInput",
    originChainId: "42161",                // Arbitrum
    destinationChainId: "1",               // Ethereum
    inputToken: "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",  // USDC on Arbitrum
    outputToken: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", // WETH on Ethereum
    amount: parseUnits("200", 6).toString(),
    depositor: account.address,
    recipient: MULTICALL_HANDLER_ETH,
  });

  const response = await fetch(
    `https://app.across.to/api/swap/approval?${params}`,
    {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        actions: [
          {
            target: ETH_RECIPIENT,
            functionSignature: "",
            args: [],
            value: "0",
            isNativeTransfer: true,
            populateCallValueDynamically: true,
          },
        ],
      }),
    }
  );

  const quote = await response.json();

  if (quote.approvalTxns?.length) {
    for (const approvalTx of quote.approvalTxns) {
      const hash = await walletClient.sendTransaction({
        to: approvalTx.to,
        data: approvalTx.data,
      });
      await publicClient.waitForTransactionReceipt({ hash });
    }
  }

  const hash = await walletClient.sendTransaction({
    to: quote.swapTx.to,
    data: quote.swapTx.data,
    value: quote.swapTx.value ? BigInt(quote.swapTx.value) : 0n,
  });

  console.log("Swap + ETH transfer tx:", hash);
}

swapAndTransferEth();

Simple Native ETH Transfer

Action Configuration

How It Works

Full Example

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