/build-on-base

Standard Ethereum RPC / ethers.js Integration

For projects using raw window.ethereum, ethers.js, or any standard EIP-1193 provider without a higher-level framework.

Requirements

• ox library installed: npm install ox

Generate the dataSuffix

Create a shared constant:

import { Attribution } from "ox/erc8021";

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

ethers.js Integration

v6 (Recommended)

import { ethers } from "ethers";
import { DATA_SUFFIX } from "./attribution";

const provider = new ethers.BrowserProvider(window.ethereum);
const signer = await provider.getSigner();

// Simple ETH transfer
const tx = await signer.sendTransaction({
  to: "0x...",
  value: ethers.parseEther("0.01"),
  data: DATA_SUFFIX,
});

Appending to existing calldata (contract calls)

If the transaction already has data, concatenate the suffix after it:

import { ethers } from "ethers";
import { DATA_SUFFIX } from "./attribution";

function withAttribution(data: string): string {
  // data is a hex string starting with '0x'
  return data + DATA_SUFFIX.slice(2); // strip '0x' from suffix before concatenating
}

const iface = new ethers.Interface(ABI);
const calldata = iface.encodeFunctionData("transfer", [recipient, amount]);

const tx = await signer.sendTransaction({
  to: contractAddress,
  data: withAttribution(calldata),
});

ethers v5

import { ethers } from "ethers";
import { DATA_SUFFIX } from "./attribution";

const provider = new ethers.providers.Web3Provider(window.ethereum);
const signer = provider.getSigner();

const tx = await signer.sendTransaction({
  to: "0x...",
  value: ethers.utils.parseEther("0.01"),
  data: DATA_SUFFIX,
});

Raw window.ethereum (EIP-1193)

Simple ETH transfer

import { DATA_SUFFIX } from "./attribution";

const accounts = await window.ethereum.request({ method: "eth_accounts" });

const txHash = await window.ethereum.request({
  method: "eth_sendTransaction",
  params: [{
    from: accounts[0],
    to: "0x...",
    value: "0x" + BigInt("10000000000000000").toString(16), // 0.01 ETH in wei hex
    data: DATA_SUFFIX,
  }],
});

With existing calldata

import { DATA_SUFFIX } from "./attribution";

const existingData = "0xabcdef..."; // your ABI-encoded contract call

const txHash = await window.ethereum.request({
  method: "eth_sendTransaction",
  params: [{
    from: accounts[0],
    to: contractAddress,
    data: existingData + DATA_SUFFIX.slice(2), // append without '0x' prefix
  }],
});

How It Works

DATA_SUFFIX is appended to the transaction's data field. Smart contracts process only the calldata they expect (ABI-encoded function selector + parameters) and ignore trailing bytes. Base's indexer reads the suffix to attribute the transaction to your builder code.