Web3Py ETH Batch Transfer Tutorial: Complete Guide with Code Examples

Introduction

Many developers struggle to implement Ethereum (ETH) batch transfers efficiently. This tutorial provides a step-by-step guide using Web3Py, complete with ready-to-use Python code.

Key Benefits:

• Save development time with pre-tested code
• Avoid gas calculation pitfalls
• Learn best practices for batch transactions

Prerequisites

Before starting, ensure you have:

1. Basic Ethereum knowledge (transactions, gas, nonce)
2. Test ETH on Ropsten network (get free test ETH here)
3. Python 3.x and Web3Py installed (pip install web3)

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Step 1: Setup Web3Py Connection

from web3 import Web3

# Connect to Infura Ropsten node
infura_url = "https://ropsten.infura.io/v3/YOUR_INFURA_PROJECT_ID"
web3 = Web3(Web3.HTTPProvider(infura_url))

Key Parameters:

• Replace YOUR_INFURA_PROJECT_ID with your Infura API key
• Verify connection: web3.isConnected() should return True

Step 2: Configure Sender Account

sender_address = "0xYourSenderAddress"
private_key = "0xYourPrivateKey"  # From MetaMask

# Get current nonce
nonce = web3.eth.getTransactionCount(sender_address)

⚠️ Security Note: Never expose private keys in production. Use environment variables.

Step 3: Batch Transfer Contract Setup

Use the pre-deployed StormMultisender contract:

contract_address = "0xa5025faba6e70b84f74e9b1113e5f7f4e7f4859f"

# Load contract ABI (simplified example)
contract_abi = [
    {
        "constant": False,
        "inputs": [
            {"name": "_to", "type": "address[]"},
            {"name": "_value", "type": "uint256[]"}
        ],
        "name": "multisendEther",
        "outputs": [],
        "type": "function"
    }
]

contract = web3.eth.contract(address=contract_address, abi=contract_abi)

Step 4: Execute Batch Transfer

recipients = ["0xRecipient1", "0xRecipient2"]  # Checksum addresses
amounts = [web3.toWei(0.1, "ether"), web3.toWei(0.2, "ether")]  # In Wei

transaction = contract.functions.multisendEther(
    recipients,
    amounts
).buildTransaction({
    "from": sender_address,
    "gas": 210000,
    "gasPrice": web3.toWei("50", "gwei"),
    "nonce": nonce,
    "value": web3.toWei(0.3, "ether")  # Total ETH sent
})

signed_txn = web3.eth.account.signTransaction(transaction, private_key)
tx_hash = web3.eth.sendRawTransaction(signed_txn.rawTransaction)

Critical Checks:

1. Total value ≥ sum of transfers + gas fees
2. Use web3.toChecksumAddress() for all addresses

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Common Errors & Solutions

FAQ

Q: How do I estimate gas costs?

estimated_gas = contract.functions.multisendEther(
    recipients, amounts
).estimateGas({"from": sender_address})

Q: Can I batch transfer ERC-20 tokens?
Yes! Use the multisendToken function in the same contract.

Q: Why is my transaction stuck?
Check Ropsten Etherscan for pending transactions and adjust gas prices.

Best Practices

1. Test first with small amounts
2. Monitor transaction status via Etherscan
3. Secure private keys using .env files

Conclusion

This guide covered end-to-end ETH batch transfers using Web3Py. For advanced use cases:

• Deploy your own multisender contract
• Add error handling for failed transactions