starknet-py

Starknet SDK for Python

📘 Documentation

• Installation
• Quickstart
• Guide
• API
• Migration guide

⚙️ Installation

Installation varies between operating systems.

See our documentation on complete instructions

💨 Quickstart

Using FullNodeClient

A Client is a facade for interacting with Starknet. FullNodeClient is a client which interacts with a Starknet full nodes like Pathfinder, Papyrus or Juno. It supports read and write operations, like querying the blockchain state or adding new transactions.

from starknet_py.net.full_node_client import FullNodeClient

node_url = "https://your.node.url"
client = FullNodeClient(node_url=node_url)

call_result = await client.get_block(block_number=1)

The default interface is asynchronous. Although it is the recommended way of using starknet.py, you can also use a synchronous version. It might be helpful to play with Starknet directly in python interpreter.

node_url = "https://your.node.url"
client = FullNodeClient(node_url=node_url)
call_result = client.get_block_sync(block_number=1)

You can check out all of the FullNodeClient’s methods here: FullNodeClient.

Creating Account

Account is the default implementation of BaseAccount interface. It supports an account contract which proxies the calls to other contracts on Starknet.

Account can be created in two ways:

• By constructor (It is required to provide an address and either key_pair or signer).
• By static method Account.deploy_account_v3

Additionally, you can use the sncast tool to create an account, which will automatically be saved to a file. There are some examples how to do it:

from starknet_py.net.account.account import Account
from starknet_py.net.full_node_client import FullNodeClient
from starknet_py.net.models.chains import StarknetChainId
from starknet_py.net.signer.key_pair import KeyPair
from starknet_py.net.signer.stark_curve_signer import StarkCurveSigner

# Creates an instance of account which is already deployed
# Account using transaction version=1 (has __validate__ function)
client = FullNodeClient(node_url="https://your.node.url")
account = Account(
    client=client,
    address="0x4321",
    key_pair=KeyPair(private_key=654, public_key=321),
    chain=StarknetChainId.SEPOLIA,
)

# There is another way of creating key_pair
key_pair = KeyPair.from_private_key(key=123)
# or
key_pair = KeyPair.from_private_key(key="0x123")

# Instead of providing key_pair it is possible to specify a signer
signer = StarkCurveSigner("0x1234", key_pair, StarknetChainId.SEPOLIA)

account = Account(
    client=client, address="0x1234", signer=signer, chain=StarknetChainId.SEPOLIA
)

Using Account

Example usage:

from starknet_py.contract import Contract
from starknet_py.net.client_models import ResourceBounds, ResourceBoundsMapping
resource_bounds = ResourceBoundsMapping(
    l1_gas=ResourceBounds(max_amount=int(1e5), max_price_per_unit=int(1e13)),
    l2_gas=ResourceBounds(max_amount=int(1e5), max_price_per_unit=int(1e13)),
    l1_data_gas=ResourceBounds(max_amount=int(1e5), max_price_per_unit=int(1e13)),
)
# Declare and deploy an example contract which implements a simple k-v store.
# Contract.declare_v3 takes string containing a compiled contract (sierra) and
# a class hash (casm_class_hash) or string containing a compiled contract (casm)
declare_result = await Contract.declare_v3(
    account,
    compiled_contract=compiled_contract,
    compiled_class_hash=class_hash,
    resource_bounds=resource_bounds,
)

await declare_result.wait_for_acceptance()
deploy_result = await declare_result.deploy_v3(
    resource_bounds=resource_bounds,
)
# Wait until deployment transaction is accepted
await deploy_result.wait_for_acceptance()

# Get deployed contract
map_contract = deploy_result.deployed_contract
k, v = 13, 4324
# Adds a transaction to mutate the state of k-v store. The call goes through account proxy, because we've used
# Account to create the contract object
await (
    await map_contract.functions["put"].invoke_v3(
        k,
        v,
        resource_bounds=resource_bounds,
    )
).wait_for_acceptance()

# Retrieves the value, which is equal to 4324 in this case
(resp,) = await map_contract.functions["get"].call(k)

# There is a possibility of invoking the multicall

# Creates a list of prepared function calls
calls = [
    map_contract.functions["put"].prepare_invoke_v3(key=10, value=20),
    map_contract.functions["put"].prepare_invoke_v3(key=30, value=40),
]

# Executes only one transaction with prepared calls
transaction_response = await account.execute_v3(
    calls=calls,
    resource_bounds=resource_bounds,
)
await account.client.wait_for_tx(transaction_response.transaction_hash)

Using Contract

Contract makes interacting with contracts deployed on Starknet much easier:

from starknet_py.contract import Contract
from starknet_py.net.client_models import ResourceBounds, ResourceBoundsMapping

contract_address = (
    "0x01336fa7c870a7403aced14dda865b75f29113230ed84e3a661f7af70fe83e7b"
)
key = 1234

# Create contract from contract's address - Contract will download contract's ABI to know its interface.
contract = await Contract.from_address(address=contract_address, provider=account)

# If the ABI is known, create the contract directly (this is the preferred way).
contract = Contract(
    address=contract_address,
    abi=abi,
    provider=account,
    cairo_version=1,
)

# All exposed functions are available at contract.functions.
# Here we invoke a function, creating a new transaction.
resource_bounds = ResourceBoundsMapping(
    l1_gas=ResourceBounds(max_amount=int(1e5), max_price_per_unit=int(1e13)),
    l2_gas=ResourceBounds(max_amount=int(1e5), max_price_per_unit=int(1e13)),
    l1_data_gas=ResourceBounds(max_amount=int(1e5), max_price_per_unit=int(1e13)),
)
invocation = await contract.functions["put"].invoke_v3(
        key,
        7,
        resource_bounds=resource_bounds,
)
# Invocation returns InvokeResult object. It exposes a helper for waiting until transaction is accepted.
await invocation.wait_for_acceptance()

# Calling contract's function doesn't create a new transaction, you get the function's result.
(saved,) = await contract.functions["get"].call(key)
# saved = 7 now

To check if invoke succeeded use wait_for_acceptance on InvokeResult and get its status.

Although asynchronous API is recommended, you can also use Contract’s synchronous API:

from starknet_py.contract import Contract
from starknet_py.net.client_models import ResourceBounds, ResourceBoundsMapping

contract_address = (
    "0x01336fa7c870a7403aced14dda865b75f29113230ed84e3a661f7af70fe83e7b"
)

key = 1234
contract = Contract.from_address_sync(address=contract_address, provider=account)

resource_bounds = ResourceBoundsMapping(
    l1_gas=ResourceBounds(max_amount=int(1e5), max_price_per_unit=int(1e13)),
    l2_gas=ResourceBounds(max_amount=int(1e5), max_price_per_unit=int(1e13)),
    l1_data_gas=ResourceBounds(max_amount=int(1e5), max_price_per_unit=int(1e13)),
)
invocation = contract.functions["put"].invoke_v3_sync(key, 7, resource_bounds=resource_bounds)
invocation.wait_for_acceptance_sync()

(saved,) = contract.functions["get"].call_sync(key)  # 7

Contract automatically serializes values to Cairo calldata. This includes adding array lengths automatically. See more info in Serialization.

Quickstart in docs - click here.