Send batch USDC transfers

Use the Multicall3From contract to batch multiple USDC transfers into one Arc transaction. This tutorial shows the full flow with viem, ethers.js, Python, and curl. You will configure a client, encode two ERC-20 transfer(...) subcalls, submit them through Multicall3From.aggregate3(...), and verify the resulting Transfer events. To learn how Multicall3From preserves your wallet as the sender, see Batched transactions.

Prerequisites

Before you begin, ensure that you’ve:

Installed Node.js v22+ for the TypeScript examples, or Python 3.10+ for the Python example.
Created an Arc Testnet wallet.
Funded the wallet with testnet USDC from the Circle Faucet.
Chosen two recipient addresses on Arc Testnet.

Step 1. Set up the project

Create a new project and install the dependencies for the client library you want to use:

mkdir arc-batched-transfers
cd arc-batched-transfers
npm init -y
npm pkg set type=module
npm install dotenv ethers tsx typescript viem

mkdir arc-batched-transfers
cd arc-batched-transfers
python3 -m venv .venv
source .venv/bin/activate
pip install web3 python-dotenv

Create an .env file:

Shell

touch .env

Add your configuration:

.env

PRIVATE_KEY=YOUR_PRIVATE_KEY
RECIPIENT_ONE_ADDRESS=RECIPIENT_ONE_ADDRESS
RECIPIENT_TWO_ADDRESS=RECIPIENT_TWO_ADDRESS
RPC_URL=https://rpc.testnet.arc.io

Replace YOUR_PRIVATE_KEY with the 0x-prefixed private key for the funded wallet. Replace each recipient value with an Arc Testnet address.

Step 2. Review the contract address and ABI

Arc Testnet uses the following predeployed contracts for this tutorial:

Contract	Address
`Multicall3From`	`0x522fAf9A91c41c443c66765030741e4AaCe147D0`
`USDC`	`0x3600000000000000000000000000000000000000`

For the full address list, see contract addresses. Create multicall3from-abi.json in your project:

multicall3from-abi.json

[
  {
    "type": "function",
    "name": "aggregate3",
    "stateMutability": "nonpayable",
    "inputs": [
      {
        "name": "calls",
        "type": "tuple[]",
        "components": [
          { "name": "target", "type": "address" },
          { "name": "allowFailure", "type": "bool" },
          { "name": "callData", "type": "bytes" }
        ]
      }
    ],
    "outputs": [
      {
        "name": "returnData",
        "type": "tuple[]",
        "components": [
          { "name": "success", "type": "bool" },
          { "name": "returnData", "type": "bytes" }
        ]
      }
    ]
  }
]

The script you build in the next steps loads this ABI file from the project root.

Step 3. Configure the client connection

Create the script file for your client library. The first chunk reads the wallet and recipient configuration from .env, sets the contract addresses, loads the Multicall3From ABI, and creates the clients that read chain state and submit transactions.

Viem
ethers.js
Python

Create viem-batch.ts:

TypeScript

import "dotenv/config";
import { readFileSync } from "node:fs";
import {
  type Address,
  createPublicClient,
  createWalletClient,
  defineChain,
  encodeFunctionData,
  erc20Abi,
  getAddress,
  http,
  parseEventLogs,
  parseUnits,
} from "viem";
import { privateKeyToAccount } from "viem/accounts";

const rpcUrl = process.env.RPC_URL ?? "https://rpc.testnet.arc.io";
const privateKey = process.env.PRIVATE_KEY as `0x${string}`;
const recipients = [
  getAddress(process.env.RECIPIENT_ONE_ADDRESS as Address),
  getAddress(process.env.RECIPIENT_TWO_ADDRESS as Address),
];

const arcTestnet = defineChain({
  id: 5042002,
  name: "Arc Testnet",
  nativeCurrency: { name: "USDC", symbol: "USDC", decimals: 18 },
  rpcUrls: { default: { http: [rpcUrl] } },
  blockExplorers: {
    default: { name: "ArcScan", url: "https://testnet.arcscan.app" },
  },
  testnet: true,
});

const multicall3FromAddress = "0x522fAf9A91c41c443c66765030741e4AaCe147D0";
const usdcAddress = "0x3600000000000000000000000000000000000000";
const multicall3FromAbi = JSON.parse(
  readFileSync("multicall3from-abi.json", "utf8"),
);

const account = privateKeyToAccount(privateKey);
const publicClient = createPublicClient({
  chain: arcTestnet,
  transport: http(rpcUrl),
});
const walletClient = createWalletClient({
  account,
  chain: arcTestnet,
  transport: http(rpcUrl),
});

Create ethers-batch.ts:

TypeScript

import "dotenv/config";
import { readFileSync } from "node:fs";
import { ethers } from "ethers";

const rpcUrl = process.env.RPC_URL ?? "https://rpc.testnet.arc.io";
const privateKey = process.env.PRIVATE_KEY as string;
const recipients = [
  ethers.getAddress(process.env.RECIPIENT_ONE_ADDRESS as string),
  ethers.getAddress(process.env.RECIPIENT_TWO_ADDRESS as string),
];

const multicall3FromAddress = "0x522fAf9A91c41c443c66765030741e4AaCe147D0";
const usdcAddress = "0x3600000000000000000000000000000000000000";
const explorerUrl = "https://testnet.arcscan.app";

const multicall3FromAbi = JSON.parse(
  readFileSync("multicall3from-abi.json", "utf8"),
);
const erc20Abi = [
  "function transfer(address to, uint256 amount) returns (bool)",
  "event Transfer(address indexed from, address indexed to, uint256 value)",
];

const provider = new ethers.JsonRpcProvider(rpcUrl, {
  chainId: 5042002,
  name: "arc-testnet",
});
const wallet = new ethers.Wallet(privateKey, provider);
const multicall3FromInterface = new ethers.Interface(multicall3FromAbi);
const erc20Interface = new ethers.Interface(erc20Abi);

Create python-batch.py:

Python

import json
import os

from dotenv import load_dotenv
from web3 import Web3
from web3.logs import DISCARD

load_dotenv()

rpc_url = os.getenv("RPC_URL", "https://rpc.testnet.arc.io")
private_key = os.environ["PRIVATE_KEY"]
recipients = [
    Web3.to_checksum_address(os.environ["RECIPIENT_ONE_ADDRESS"]),
    Web3.to_checksum_address(os.environ["RECIPIENT_TWO_ADDRESS"]),
]

multicall3_from_address = Web3.to_checksum_address(
    "0x522fAf9A91c41c443c66765030741e4AaCe147D0"
)
usdc_address = Web3.to_checksum_address("0x3600000000000000000000000000000000000000")
explorer_url = "https://testnet.arcscan.app"

with open("multicall3from-abi.json", encoding="utf-8") as abi_file:
    multicall3_from_abi = json.load(abi_file)
erc20_abi = [
    {

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Send batch USDC transfers

Prerequisites

Step 1. Set up the project

Step 2. Review the contract address and ABI

Step 3. Configure the client connection

​Prerequisites

​Step 1. Set up the project

​Step 2. Review the contract address and ABI

​Step 3. Configure the client connection

Prerequisites

Step 1. Set up the project

Step 2. Review the contract address and ABI

Step 3. Configure the client connection