Deposit ETH into Aave

This example swaps tokens crosschain to ETH, then deposits the received ETH into Aave's WETH Gateway — all in a single user transaction. The key mechanism is populateCallValueDynamically: true, which forwards the entire swapped ETH balance as the contract call's msg.value.

Action Configuration

action.json

{
  "actions": [
    {
      "target": "0x5283BEcEd7ADF6D003225C13896E536f2D4264FF",
      "functionSignature": "function depositETH(address, address onBehalfOf, uint16 referralCode)",
      "args": [
        {
          "value": "0x0000000000000000000000000000000000000000",
          "populateDynamically": false
        },
        {
          "value": "0x718648C8c531F91b528A7757dD2bE813c3940608",
          "populateDynamically": false
        },
        {
          "value": "0",
          "populateDynamically": false
        }
      ],
      "value": "0",
      "isNativeTransfer": false,
      "populateCallValueDynamically": true
    }
  ]
}

How It Works

target — Aave's WETH Gateway contract (0x5283BEcEd7ADF6D003225C13896E536f2D4264FF)
functionSignature — depositETH(address, address onBehalfOf, uint16 referralCode)
First arg — Aave lending pool address (zero address in this case, resolved by the gateway)
Second arg — onBehalfOf — the address that receives the aToken deposit position
Third arg — Aave referral code (0 for none)
populateCallValueDynamically: true — The entire ETH balance from the swap is automatically sent as msg.value to the depositETH call. No need to specify a static value

Full Example

swap-and-deposit-aave.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 = "0x924a9f036260DdD5808007E1AA95f08eD08aA569";
const AAVE_WETH_GATEWAY = "0x5283BEcEd7ADF6D003225C13896E536f2D4264FF";
const DEPOSIT_BENEFICIARY = "0x718648C8c531F91b528A7757dD2bE813c3940608";

async function swapAndDepositToAave() {
  const params = new URLSearchParams({
    tradeType: "exactInput",
    originChainId: "42161",                // Arbitrum
    destinationChainId: "1",               // Ethereum
    inputToken: "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",  // USDC on Arbitrum
    outputToken: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", // WETH on Ethereum
    amount: parseUnits("500", 6).toString(),
    depositor: account.address,
    recipient: MULTICALL_HANDLER,
  });

  const response = await fetch(
    `https://app.across.to/api/swap/approval?${params}`,
    {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        actions: [
          {
            target: AAVE_WETH_GATEWAY,
            functionSignature:
              "function depositETH(address, address onBehalfOf, uint16 referralCode)",
            args: [
              {
                value: "0x0000000000000000000000000000000000000000",
                populateDynamically: false,
              },
              {
                value: DEPOSIT_BENEFICIARY,
                populateDynamically: false,
              },
              {
                value: "0",
                populateDynamically: false,
              },
            ],
            value: "0",
            isNativeTransfer: false,
            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 + Aave deposit tx:", hash);
}

swapAndDepositToAave();

populateCallValueDynamically: true tells the MulticallHandler to use the entire ETH balance received from the swap as msg.value for the depositETH call. This is the key mechanism for forwarding native ETH into DeFi protocols.

Deposit ETH into Aave

Action Configuration

How It Works

Full Example

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