Learn Web3py - 10 Code Examples & CST Typing Practice Test

Web3.py is a Python library for interacting with the Ethereum blockchain. It allows developers to deploy, interact with, and query smart contracts, manage accounts, and handle blockchain transactions programmatically.

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Python Web3.py Simple Smart Contract Interaction Web3.py Check Ether Balance Web3.py Deploy Simple Contract Web3.py Listen to Contract Events Web3.py Send Ether Transaction Web3.py Interact with ERC20 Token Web3.py Estimate Gas Web3.py Check Transaction Receipt Web3.py Call Contract View Function Web3.py Deploy Contract with Constructor Args

Learn WEB3PY with Real Code Examples

Updated Nov 25, 2025

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Code Sample Descriptions

Python Web3.py Simple Smart Contract Interaction

from web3 import Web3

# Connect to local Ethereum node
w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))

# Contract ABI and address (example)
abi = '[...]'
address = '0xYourContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

# Read value from contract
value = contract.functions.getValue().call()
print('Contract value:', value)

# Send transaction to contract
tx_hash = contract.functions.setValue(42).transact({'from': w3.eth.accounts[0]})
w3.eth.wait_for_transaction_receipt(tx_hash)

A minimal example showing how to connect to Ethereum and interact with a deployed smart contract using Web3.py.

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Web3.py Check Ether Balance

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
account = '0xYourAccountAddress'
balance = w3.eth.get_balance(account)
print('Balance:', w3.fromWei(balance, 'ether'), 'ETH')

Check the Ether balance of an account using Web3.py.

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Web3.py Deploy Simple Contract

from web3 import Web3
from solcx import compile_source

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))

source_code = 'contract Simple { uint public x; function set(uint val) public { x = val; } }'
compiled = compile_source(source_code)
contract_interface = compiled['<stdin>:Simple']
Simple = w3.eth.contract(abi=contract_interface['abi'], bytecode=contract_interface['bin'])
tx_hash = Simple.constructor().transact({'from': w3.eth.accounts[0]})
tx_receipt = w3.eth.wait_for_transaction_receipt(tx_hash)
print('Contract deployed at:', tx_receipt.contractAddress)

Deploy a simple Solidity contract using Web3.py.

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Web3.py Listen to Contract Events

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
abi = '[...]'
address = '0xYourContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

event_filter = contract.events.YourEvent.createFilter(fromBlock='latest')
for event in event_filter.get_new_entries():
    print(event)

Subscribe to events emitted by a smart contract.

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Web3.py Send Ether Transaction

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
from_account = w3.eth.accounts[0]
to_account = w3.eth.accounts[1]

tx = {
    'from': from_account,
    'to': to_account,
    'value': w3.toWei(0.1, 'ether'),
    'gas': 21000,
    'gasPrice': w3.toWei('50', 'gwei')
}
tx_hash = w3.eth.send_transaction(tx)
w3.eth.wait_for_transaction_receipt(tx_hash)

Send Ether from one account to another using Web3.py.

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Web3.py Interact with ERC20 Token

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
abi = '[...]'
address = '0xTokenContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

# Check token balance
balance = contract.functions.balanceOf(w3.eth.accounts[0]).call()
print('Token Balance:', balance)

# Transfer tokens
tx_hash = contract.functions.transfer(w3.eth.accounts[1], 100).transact({'from': w3.eth.accounts[0]})
w3.eth.wait_for_transaction_receipt(tx_hash)

Read balance and transfer ERC20 tokens.

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Web3.py Estimate Gas

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
abi = '[...]'
address = '0xYourContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

gas_estimate = contract.functions.setValue(42).estimateGas({'from': w3.eth.accounts[0]})
print('Estimated Gas:', gas_estimate)

Estimate gas required for a contract function call.

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Web3.py Check Transaction Receipt

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
tx_hash = '0xYourTransactionHash'
receipt = w3.eth.get_transaction_receipt(tx_hash)
print(receipt)

Fetch and inspect a transaction receipt.

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Web3.py Call Contract View Function

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
abi = '[...]'
address = '0xYourContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

result = contract.functions.getValue().call()
print('Value:', result)

Call a read-only function from a deployed smart contract.

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Web3.py Deploy Contract with Constructor Args

from web3 import Web3
from solcx import compile_source

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
source = 'contract Greeter { string public greeting; constructor(string memory _g) { greeting = _g; } }'
compiled = compile_source(source)
contract_interface = compiled['<stdin>:Greeter']
Greeter = w3.eth.contract(abi=contract_interface['abi'], bytecode=contract_interface['bin'])
tx_hash = Greeter.constructor('Hello Web3').transact({'from': w3.eth.accounts[0]})
tx_receipt = w3.eth.wait_for_transaction_receipt(tx_hash)
print('Deployed at:', tx_receipt.contractAddress)

Deploy a Solidity contract providing constructor parameters.

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Frequently Asked Questions about Web3py

What is Web3py?

What are the primary use cases for Web3py?

Deploying and interacting with smart contracts. Reading blockchain data and logs. Automating DeFi and trading operations. NFT minting and marketplaces. Backend blockchain integrations in Python

What are the strengths of Web3py?

Pythonic syntax easy for Python developers. Supports multiple Ethereum node connections. Flexible event and contract interaction. Easy to integrate with Python data pipelines. Strong community support and tutorials

What are the limitations of Web3py?

Limited to Ethereum and EVM-compatible chains. Performance bound by Python execution and node RPC. Not suitable for high-frequency on-chain computation. No native GUI; backend-focused. Dependent on node availability and sync status

How can I practice Web3py typing speed?

CodeSpeedTest offers 10+ real Web3py code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Code Sample Descriptions

Python Web3.py Simple Smart Contract Interaction

from web3 import Web3

# Connect to local Ethereum node
w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))

# Contract ABI and address (example)
abi = '[...]'
address = '0xYourContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

# Read value from contract
value = contract.functions.getValue().call()
print('Contract value:', value)

# Send transaction to contract
tx_hash = contract.functions.setValue(42).transact({'from': w3.eth.accounts[0]})
w3.eth.wait_for_transaction_receipt(tx_hash)

A minimal example showing how to connect to Ethereum and interact with a deployed smart contract using Web3.py.

Let’s Try →

Web3.py Check Ether Balance

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
account = '0xYourAccountAddress'
balance = w3.eth.get_balance(account)
print('Balance:', w3.fromWei(balance, 'ether'), 'ETH')

Check the Ether balance of an account using Web3.py.

Let’s Try →

Web3.py Deploy Simple Contract

from web3 import Web3
from solcx import compile_source

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))

source_code = 'contract Simple { uint public x; function set(uint val) public { x = val; } }'
compiled = compile_source(source_code)
contract_interface = compiled['<stdin>:Simple']
Simple = w3.eth.contract(abi=contract_interface['abi'], bytecode=contract_interface['bin'])
tx_hash = Simple.constructor().transact({'from': w3.eth.accounts[0]})
tx_receipt = w3.eth.wait_for_transaction_receipt(tx_hash)
print('Contract deployed at:', tx_receipt.contractAddress)

Deploy a simple Solidity contract using Web3.py.

Let’s Try →

Web3.py Listen to Contract Events

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
abi = '[...]'
address = '0xYourContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

event_filter = contract.events.YourEvent.createFilter(fromBlock='latest')
for event in event_filter.get_new_entries():
    print(event)

Subscribe to events emitted by a smart contract.

Let’s Try →

Web3.py Send Ether Transaction

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
from_account = w3.eth.accounts[0]
to_account = w3.eth.accounts[1]

tx = {
    'from': from_account,
    'to': to_account,
    'value': w3.toWei(0.1, 'ether'),
    'gas': 21000,
    'gasPrice': w3.toWei('50', 'gwei')
}
tx_hash = w3.eth.send_transaction(tx)
w3.eth.wait_for_transaction_receipt(tx_hash)

Send Ether from one account to another using Web3.py.

Let’s Try →

Web3.py Interact with ERC20 Token

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
abi = '[...]'
address = '0xTokenContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

# Check token balance
balance = contract.functions.balanceOf(w3.eth.accounts[0]).call()
print('Token Balance:', balance)

# Transfer tokens
tx_hash = contract.functions.transfer(w3.eth.accounts[1], 100).transact({'from': w3.eth.accounts[0]})
w3.eth.wait_for_transaction_receipt(tx_hash)

Read balance and transfer ERC20 tokens.

Let’s Try →

Web3.py Estimate Gas

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
abi = '[...]'
address = '0xYourContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

gas_estimate = contract.functions.setValue(42).estimateGas({'from': w3.eth.accounts[0]})
print('Estimated Gas:', gas_estimate)

Estimate gas required for a contract function call.

Let’s Try →

Web3.py Check Transaction Receipt

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
tx_hash = '0xYourTransactionHash'
receipt = w3.eth.get_transaction_receipt(tx_hash)
print(receipt)

Fetch and inspect a transaction receipt.

Let’s Try →

Web3.py Call Contract View Function

from web3 import Web3

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
abi = '[...]'
address = '0xYourContractAddress'
contract = w3.eth.contract(address=address, abi=abi)

result = contract.functions.getValue().call()
print('Value:', result)

Call a read-only function from a deployed smart contract.

Let’s Try →

Web3.py Deploy Contract with Constructor Args

from web3 import Web3
from solcx import compile_source

w3 = Web3(Web3.HTTPProvider('http://127.0.0.1:8545'))
source = 'contract Greeter { string public greeting; constructor(string memory _g) { greeting = _g; } }'
compiled = compile_source(source)
contract_interface = compiled['<stdin>:Greeter']
Greeter = w3.eth.contract(abi=contract_interface['abi'], bytecode=contract_interface['bin'])
tx_hash = Greeter.constructor('Hello Web3').transact({'from': w3.eth.accounts[0]})
tx_receipt = w3.eth.wait_for_transaction_receipt(tx_hash)
print('Deployed at:', tx_receipt.contractAddress)

Deploy a Solidity contract providing constructor parameters.

Let’s Try →

Frequently Asked Questions about Web3py

What is Web3py?

What are the primary use cases for Web3py?

Deploying and interacting with smart contracts. Reading blockchain data and logs. Automating DeFi and trading operations. NFT minting and marketplaces. Backend blockchain integrations in Python

What are the strengths of Web3py?

What are the limitations of Web3py?

How can I practice Web3py typing speed?

CodeSpeedTest offers 10+ real Web3py code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.