> ## Documentation Index
> Fetch the complete documentation index at: https://docs.swaps.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Cross-Chain Calls

> Execute cross-chain transactions.

export const Callout = ({type = 'info', children}) => {
  const borderColor = ({
    info: '#007acc',
    warning: '#FFC263',
    danger: '#d9534f',
    success: '#00C256'
  })[type] || '#ccc';
  const bgColor = ({
    info: '#f3f9ff',
    warning: '#FFF2DE',
    danger: '#f7f2f1',
    note: '#f8f8f8',
    tip: '#f1f1f8',
    success: '#E0FFEE'
  })[type] || '#f3f9ff';
  return <div style={{
    borderLeft: `4px solid ${borderColor}`,
    backgroundColor: bgColor,
    padding: '0.5rem',
    borderRadius: '12px',
    margin: '1rem 0',
    fontSize: '14px'
  }}>
      {children}
    </div>;
};

**API Reference:** [Get Action](/swap-api-reference/get-action#swap)

This guide will only cover the process of generating calldata transactions. You can submit this transaction exactly as outlined in the [swap broadcast flows](/guides/swap#broadcast-on-evm).

## Create a cross-chain transaction

In this example, we are going to deposit 1 ETH liquidity in Aave on Base using USDC on Arbitrum.

<Steps>
  <Step title="Build your destination transaction.">
    We'll use helper functions from [Viem](https://viem.sh/); however, you can use your preferred library.

    ```typescript theme={null}
    import { account, walletClient } from "./your_viem_config";
    import { encodeFunctionData, parseAbiItem, Hex } from "viem";

    const aaveOnBase = "0xA238Dd80C259a72e81d7e4664a9801593F98d1c5";
    const ethDepositAmount = 1000000000000000000n;
    const sender = "0xd8da6bf26964af9d7eed9e03e53415d37aa96045"; // generally the user's connected wallet address

    const supplyTxCalldata: Hex = encodeFunctionData({
      abi: parseAbiItem(
        "function supply(address asset, uint256 amount, address onBehalfOf, uint16 referralCode)"
      ),
      functionName: "supply",
      args: [
        "0x0000000000000000000000000000000000000000",
        ethDepositAmount,
        sender,
        0n,
      ],
    });
    ```
  </Step>

  <Step title="Configure the transaction request">
    <Callout type="warning">
      Cross-chain calls can handle all non-permissioned functions. If your function
      includes a `msg.sender` check, please consider updating it to a multi-chain
      compatible sender authentication method based on [this
      guide](/guides/best-practices#permissioned-functions).
    </Callout>

    **Calldata Transaction Config**

    ```typescript theme={null}
    const txConfig: ActionRequest = {
      actionType: "evm-calldata-tx",
      sender,
      srcToken: "0xaf88d065e77c8cc2239327c5edb3a432268e5831", // USDC on Arbitrum
      dstToken: "0x0000000000000000000000000000000000000000", // ETH on Base
      srcChainId: 42161, // Arbitrum Chain ID
      dstChainId: 8453, // Base Chain ID
      slippage: 100, // bps
      to: aaveOnBase,
      data: supplyTxCalldata,
      value: ethDepositAmount,
    };
    ```
  </Step>

  <Step title="Generate the transaction">
    Please visit the [Get Action](/swap-api-reference/get-action) API reference for type definitions, including the `ActionRequest` and `ActionResponse`. This API endpoint will return a transaction object we will use to actually execute this transaction.

    ```typescript theme={null}
    async function getAction({ actionRequest }): Promise<ActionResponse> {
      const url = new URL("https://api-v2.swaps.xyz/api/getAction");

      Object.entries(actionRequest).forEach(([key, value]) => {
        url.searchParams.set(key, String(value));
      }

      const requestOptions = {
        method: "GET",
        headers: { "x-api-key": SWAPS_API_KEY },
      };

      const response = await fetch(url.toString(), requestOptions);

      return await response.json();
    }
    ```

    <Callout type="success">
      **That's it!** You now have a transaction you can broadcast on your source
      chain. Please see the [swap broadcast flows](/guides/swap#broadcast-on-evm)
      for how you can send this transaction on chain.
    </Callout>
  </Step>
</Steps>