/build-on-base

Smart Wallets (EIP-5792 / ERC-4337)

For smart wallet transactions using sendCalls (EIP-5792), pass the dataSuffix via the capabilities object.

Wagmi useSendCalls

import { useSendCalls } from "wagmi";
import { parseEther } from "viem";
import { Attribution } from "ox/erc8021";

const DATA_SUFFIX = Attribution.toDataSuffix({
  codes: ["YOUR-BUILDER-CODE"],
});

function App() {
  const { sendCalls } = useSendCalls();

  return (
    <button onClick={() => sendCalls({
      calls: [
        {
          to: "0x...",
          value: parseEther("1"),
        },
        {
          data: "0xdeadbeef",
          to: "0x...",
        },
      ],
      capabilities: {
        dataSuffix: {
          value: DATA_SUFFIX,
          optional: true, // wallet proceeds even if it doesn't support dataSuffix
        },
      },
    })}>
      Send calls
    </button>
  );
}

Where the Suffix Goes

Important: For ERC-4337 user operations, the suffix is appended to the outer callData field of the UserOperation, not to individual call data within batched calls.

Wallet Support

The connected wallet must support the dataSuffix capability via ERC-5792 wallet_sendCalls. Setting optional: true means the transaction proceeds even if the wallet doesn't support it.

Currently supported by: Base Smart Wallet, Coinbase Wallet, and other ERC-5792 compliant wallets.

Client-Level Alternative

If using Wagmi with dataSuffix in the config (see wagmi.md), useSendCalls transactions are also attributed automatically without needing to pass capabilities.

Privy Smart Wallets

If using Privy's embedded smart wallets, the dataSuffix plugin handles everything automatically. See privy.md. No need to manually pass capabilities.