Cookbook
Overview
This page will guide you through the process of handling common tasks using the MultiversX Python SDK (libraries).
All examples depicted here are captured in (interactive) Jupyter notebooks.
We are going to make use of the packages multiversx-sdk-core, multiversx-sdk-wallet and multiversx-sdk-network-providers (available as of January 2023), which were previously nicknamed erdpy-eggs. These packages can be installed directly from GitHub or from PyPI.
Example for installing the packages directly from GitHub, using a requirements.txt file:
git+https://git@github.com/multiversx/mx-sdk-py-core.git@v1.2.3#egg=multiversx_sdk_core
git+https://git@github.com/multiversx/mx-sdk-py-wallet.git@v4.5.6#egg=multiversx_sdk_wallet
git+https://git@github.com/multiversx/mx-sdk-py-network-providers.git@v7.8.9#egg=multiversx_sdk_network_providers
These packages are distributed separately and have individual release schedules (make sure to check the release tags on GitHub), but they are designed to work together, with as little impedance mismatch as possible.
Documentation is preliminary and subject to change (the packages might suffer a series of breaking changes in January 2023).
Addresses
Create an Address object from a bech32-encoded string:
from multiversx_sdk_core import Address
address = Address.from_bech32("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th")
print("Address (bech32-encoded)", address.bech32())
print("Public key (hex-encoded):", address.hex())
print("Public key (hex-encoded):", address.pubkey.hex())
... or from a hex-encoded string - note that you have to provide the address prefix, also known as the HRP (human-readable part of the address):
address = Address.from_hex("0139472eff6886771a982f3083da5d421f24c29181e63888228dc81ca60d69e1", "erd");
... or from a raw public key:
pubkey = bytes.fromhex("0139472eff6886771a982f3083da5d421f24c29181e63888228dc81ca60d69e1")
address = Address(pubkey, "erd")
Alternatively, you can use an AddressFactory (initialized with a specific HRP) to create addresses:
from multiversx_sdk_core import AddressFactory
factory = AddressFactory("erd")
address = factory.create_from_bech32("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th")
address = factory.create_from_hex("0139472eff6886771a982f3083da5d421f24c29181e63888228dc81ca60d69e1")
address = factory.create_from_pubkey(bytes.fromhex("0139472eff6886771a982f3083da5d421f24c29181e63888228dc81ca60d69e1"))
Addresses can be converted from one representation to another as follows:
print(address.bech32())
print(address.hex())
... or using a converter:
from multiversx_sdk_core import AddressConverter
converter = AddressConverter("erd")
pubkey = converter.bech32_to_pubkey("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th")
bech32 = converter.pubkey_to_bech32(bytes.fromhex("0139472eff6886771a982f3083da5d421f24c29181e63888228dc81ca60d69e1"))
Getting the shard of an address:
print("Shard:", address.get_shard())
Checking whether an address is a smart contract:
address = Address.from_bech32("erd1qqqqqqqqqqqqqpgquzmh78klkqwt0p4rjys0qtp3la07gz4d396qn50nnm")
print("Is contract:", address.is_smart_contract())
EGLD / ESDT transfers
Create an EGLD transfer:
from multiversx_sdk_core import Address, TokenPayment, Transaction
tx = Transaction(
nonce=90,
sender=Address.from_bech32("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th"),
receiver=Address.from_bech32("erd1spyavw0956vq68xj8y4tenjpq2wd5a9p2c6j8gsz7ztyrnpxrruqzu66jx"),
value=TokenPayment.egld_from_amount("1.0"),
gas_limit=50000,
gas_price=1000000000,
chain_id="D",
version=1
)
print(tx.to_dictionary())
We'll see later how to sign and broadcast a transaction.
Create an EGLD transfer, but this time with a payload (data):
from multiversx_sdk_core import TransactionPayload
data = TransactionPayload.from_str("for the book")
tx = Transaction(
nonce=91,
sender=Address.from_bech32("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th"),
receiver=Address.from_bech32("erd1spyavw0956vq68xj8y4tenjpq2wd5a9p2c6j8gsz7ztyrnpxrruqzu66jx"),
value=TokenPayment.egld_from_amount("3.0"),
data=data,
gas_limit=50000 + 1500 * data.length(),
gas_price=1000000000,
chain_id="D",
version=1
)
print(tx.to_dictionary())
Alternatively, we can create an EGLD transfer using a transaction builder (as we will see below, transaction builders are more commonly used). But before that, we have to create a configuration object (for any builder that we might use):
from multiversx_sdk_core.transaction_builders import DefaultTransactionBuildersConfiguration
config = DefaultTransactionBuildersConfiguration(chain_id="D")
The transaction builder is parametrized at instantiation, and the transaction is obtained by invoking the build() method:
from multiversx_sdk_core.transaction_builders import EGLDTransferBuilder
alice = Address.from_bech32("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th")
bob = Address.from_bech32("erd1spyavw0956vq68xj8y4tenjpq2wd5a9p2c6j8gsz7ztyrnpxrruqzu66jx")
payment = TokenPayment.egld_from_amount("1.00")
# With "data" field
builder = EGLDTransferBuilder(
config=config,
sender=alice,
receiver=bob,
payment=payment,
data="for the book",
# Nonce can be set now, or later, prior signing
nonce=42
)
tx = builder.build()
print("Transaction:", tx.to_dictionary())
print("Transaction data:", tx.data)
Create a single ESDT transfer:
from multiversx_sdk_core.transaction_builders import ESDTTransferBuilder
payment = TokenPayment.fungible_from_amount("TEST-8b028f", "100.00", 2)
builder = ESDTTransferBuilder(
config=config,
sender=alice,
receiver=bob,
payment=payment
)
tx = builder.build()
print("Transaction:", tx.to_dictionary())
print("Transaction data:", tx.data)
Create a single NFT transfer:
from multiversx_sdk_core.transaction_builders import ESDTNFTTransferBuilder
payment = TokenPayment.non_fungible("TEST-38f249", 1)
builder = ESDTNFTTransferBuilder(
config=config,
sender=alice,
destination=bob,
payment=payment
)
tx = builder.build()
print("Transaction:", tx.to_dictionary())
print("Transaction data:", tx.data)
Create a single SFT transfer (almost the same as above, the only difference being that for the token payment object we additionally use a quantity, as an integer):
payment = TokenPayment.semi_fungible("SEMI-9efd0f", 1, 5)
builder = ESDTNFTTransferBuilder(
config=config,
sender=alice,
destination=bob,
payment=payment
)
tx = builder.build()
print("Transaction:", tx.to_dictionary())
print("Transaction data:", tx.data)
Create a multiple ESDT / NFT transfer:
from multiversx_sdk_core.transaction_builders import MultiESDTNFTTransferBuilder
payment_one = TokenPayment.non_fungible("TEST-38f249", 1)
payment_two = TokenPayment.fungible_from_amount("BAR-c80d29", "10.00", 18)
builder = MultiESDTNFTTransferBuilder(
config=config,
sender=alice,
destination=bob,
payments=[payment_one, payment_two]
)
tx = builder.build()
print("Transaction:", tx.to_dictionary())
print("Transaction data:", tx.data)
Contract deployments and interactions
Create a transaction to deploy a smart contract:
from pathlib import Path
from multiversx_sdk_core import CodeMetadata
from multiversx_sdk_core.transaction_builders import ContractDeploymentBuilder
metadata = CodeMetadata(upgradeable=True, readable=True, payable=True, payable_by_contract=True)
builder = ContractDeploymentBuilder(
config,
owner=alice,
deploy_arguments=[42, "test"],
code_metadata=metadata,
code=Path("./contracts/contract.wasm").read_bytes(),
gas_limit=10000000
)
tx = builder.build()
print("Transaction:", tx.to_dictionary())
print("Transaction data:", tx.data)
Create a transaction to upgrade an existing smart contract:
from multiversx_sdk_core.transaction_builders import ContractUpgradeBuilder
contract_address = Address.from_bech32("erd1qqqqqqqqqqqqqpgquzmh78klkqwt0p4rjys0qtp3la07gz4d396qn50nnm")
owner = Address.from_bech32("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th")
metadata = CodeMetadata(upgradeable=True, readable=True, payable=True, payable_by_contract=True)
builder = ContractUpgradeBuilder(
config,
contract=contract_address,
owner=owner,
upgrade_arguments=[42, "test"],
code_metadata=metadata,
code=Path("./contracts/contract.wasm").read_bytes(),
gas_limit=10000000
)
tx = builder.build()
print("Transaction:", tx.to_dictionary())
print("Transaction data:", tx.data)
Create a transaction that invokes a smart contract function:
from multiversx_sdk_core.transaction_builders import ContractCallBuilder
contract_address = Address.from_bech32("erd1qqqqqqqqqqqqqpgquzmh78klkqwt0p4rjys0qtp3la07gz4d396qn50nnm")
builder = ContractCallBuilder(
config,
contract=contract_address,
function_name="foo",
caller=alice,
call_arguments=[42, "test", bob],
gas_limit=10000000
)
tx = builder.build()
print("Transaction:", tx.to_dictionary())
print("Transaction data:", tx.data)
Now, let's create a call that also transfers one or more tokens (transfer & execute):
transfers = [
TokenPayment.non_fungible("TEST-38f249", 1),
TokenPayment.fungible_from_amount("BAR-c80d29", "10.00", 18)
]
builder = ContractCallBuilder(
config,
contract=contract_address,
function_name="hello",
caller=alice,
call_arguments=[42, "test", bob],
gas_limit=10000000,
esdt_transfers=transfers
)
tx = builder.build()
print("Transaction:", tx.to_dictionary())
print("Transaction data:", tx.data)
Contract queries
In order to create a contract query and run it against a network provider (more details about network providers can be found below), do as follows:
from multiversx_sdk_core import ContractQueryBuilder
from multiversx_sdk_core.interfaces import IAddress
from multiversx_sdk_network_providers import ApiNetworkProvider
contract: IAddress = Address.from_bech32("erd1qqqqqqqqqqqqqpgqnzm7yhayarylux045qlm4lgzmtcsgrqg396qr9kupx")
builder = ContractQueryBuilder(
contract=contract,
function="getSum",
call_arguments=[],
caller=alice
)
query = builder.build()
network_provider = ApiNetworkProvider("https://devnet-api.multiversx.com")
response = network_provider.query_contract(query)
print("Return code:", response.return_code)
print("Return data:", response.return_data)
Creating wallets
Mnemonic generation is based on trezor/python-mnemonic and can be achieved as follows:
from multiversx_sdk_wallet import Mnemonic
mnemonic = Mnemonic.generate()
words = mnemonic.get_words()
print(words)
The mnemonic can be saved to a keystore file:
from multiversx_sdk_wallet import UserWallet
wallet = UserWallet.from_mnemonic(mnemonic.get_text(), "password")
wallet.save(Path("./output/walletWithMnemonic.json"))
Given a mnemonic, one can derive keypairs:
secret_key = mnemonic.derive_key(0)
public_key = secret_key.generate_public_key()
print("Secret key", secret_key.hex())
print("Public key", public_key.hex())
A keypair can be saved as a JSON wallet:
wallet = UserWallet.from_secret_key(secret_key, "password")
wallet.save(Path("./output/wallet.json"), address_hrp="erd")
... or as a PEM wallet (usually not recommended):
from multiversx_sdk_wallet import UserPEM
label = Address(public_key.buffer, "erd").bech32()
pem = UserPEM(label=label, secret_key=secret_key)
pem.save(Path("./output/wallet.pem"))
Loading wallets
This is not a very common use-case - you might refer to signing objects instead.
Load a keystore that holds an encrypted mnemonic (and perform wallet derivation at the same time):
from multiversx_sdk_wallet import UserWallet
secret_key = UserWallet.load_secret_key(Path("./testwallets/withMnemonic.json"), "password", address_index=0)
address = secret_key.generate_public_key().to_address("erd")
print("Secret key", secret_key.hex())
print("Address", address)
Load a keystore that holds an encrypted secret key:
secret_key = UserWallet.load_secret_key(Path("./testwallets/alice.json"), "password")
address = secret_key.generate_public_key().to_address("erd")
print("Secret key", secret_key.hex())
print("Address", address)
Load the secret key from a PEM file:
from multiversx_sdk_wallet import UserPEM
pem = UserPEM.from_file(Path("./testwallets/alice.pem"))
print("Secret key", pem.secret_key.hex())
print("Public key", pem.public_key.hex())
Signing objects
Creating a UserSigner from a JSON wallet:
from multiversx_sdk_wallet import UserSigner
signer = UserSigner.from_wallet(Path("./testwallets/alice.json"), "password")
Creating a UserSigner from a PEM file:
signer = UserSigner.from_pem_file(Path("./testwallets/alice.pem"))
Signable objects (messages, transactions) must adhere to the following interface:
class ISignable(Protocol):
def serialize_for_signing(self) -> bytes: ...
Both Transaction and Message - defined in multiversx_sdk_core - implement ISignable.
Signing a transaction:
from multiversx_sdk_core import Transaction
tx = Transaction(
nonce=90,
sender=Address.from_bech32("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th"),
receiver=Address.from_bech32("erd1spyavw0956vq68xj8y4tenjpq2wd5a9p2c6j8gsz7ztyrnpxrruqzu66jx"),
value=TokenPayment.egld_from_amount("1.0"),
gas_limit=50000,
gas_price=1000000000,
chain_id="D",
version=1
)
tx.signature = signer.sign(tx)
print("Signature", tx.signature.hex())
Signing an arbitrary message:
from multiversx_sdk_core import MessageV1
message = MessageV1.from_string("hello")
message.signature = signer.sign(message)
print("Signature", message.signature.hex())
Verifying signatures
Creating a UserVerifier:
from multiversx_sdk_core import Address
from multiversx_sdk_wallet import UserVerifier
alice = Address.from_bech32("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th")
bob = Address.from_bech32("erd1spyavw0956vq68xj8y4tenjpq2wd5a9p2c6j8gsz7ztyrnpxrruqzu66jx")
alice_verifier = UserVerifier.from_address(alice)
bob_verifier = UserVerifier.from_address(bob)
For objects to support signature verification, they must adhere to the following interface:
class IVerifiable(Protocol):
signature: ISignature
def serialize_for_signing(self) -> bytes: ...
Both Transaction and Message - defined in multiversx_sdk_core - implement IVerifiable.
Verifying a signature:
print(f"Is signature of Alice?", alice_verifier.verify(tx))
print(f"Is signature of Alice?", alice_verifier.verify(message))
print(f"Is signature of Bob?", bob_verifier.verify(tx))
print(f"Is signature of Bob?", bob_verifier.verify(message))
Creating network providers
It's recommended to use the multiversx_sdk_network_providers components as a starting point. As your application matures, switch to using your own network provider (e.g. deriving from the default ones), tailored to your requirements.
Creating an API provider:
from multiversx_sdk_network_providers import ApiNetworkProvider
provider = ApiNetworkProvider("https://devnet-api.multiversx.com");
Creating a Proxy provider:
from multiversx_sdk_network_providers import ProxyNetworkProvider
provider = ProxyNetworkProvider("https://devnet-gateway.multiversx.com");
Fetching network parameters
In order to fetch network parameters, do as follows:
config = provider.get_network_config();
print("Chain ID", config.chain_id);
print("Min gas price:", config.min_gas_price);
Fetching account state
The following snippet fetches (from the Network) the nonce and the balance of an account:
account_on_network = provider.get_account(alice)
print("Nonce", account_on_network.nonce)
print("Balance", account_on_network.balance)
When sending a number of transactions, you usually have to first fetch the account nonce from the network (see above), then manage it locally (e.g. increment upon signing & broadcasting a transaction):
from multiversx_sdk_core import AccountNonceHolder
nonce_holder = AccountNonceHolder(account_on_network.nonce)
tx.nonce = nonce_holder.get_nonce_then_increment()
# Then, sign & broadcast the transaction(s).
For further reference, please see nonce management.
Broadcasting transactions
Broadcast a single transaction:
alice = Address.from_bech32("erd1qyu5wthldzr8wx5c9ucg8kjagg0jfs53s8nr3zpz3hypefsdd8ssycr6th")
tx = Transaction(
sender=alice,
receiver=alice,
gas_limit=50000,
chain_id="D"
)
alice_on_network = provider.get_account(alice)
tx.nonce = alice_on_network.nonce
tx.signature = signer.sign(tx)
hash = provider.send_transaction(tx)
print("Transaction hash:", hash)
Broadcast multiple transactions:
tx_1 = Transaction(
sender=alice,
receiver=alice,
gas_limit=50000,
chain_id="D"
)
tx_2 = Transaction(
sender=alice,
receiver=alice,
gas_limit=50000,
chain_id="D"
)
tx_3 = Transaction(
sender=alice,
receiver=alice,
gas_limit=50000,
chain_id="D"
)
alice_on_network = provider.get_account(alice)
nonce_holder = AccountNonceHolder(account_on_network.nonce)
tx_1.nonce = nonce_holder.get_nonce_then_increment()
tx_2.nonce = nonce_holder.get_nonce_then_increment()
tx_3.nonce = nonce_holder.get_nonce_then_increment()
tx_1.signature = signer.sign(tx_1)
tx_2.signature = signer.sign(tx_2)
tx_3.signature = signer.sign(tx_3)
hashes = provider.send_transactions([tx_1, tx_2, tx_3])
print("Transactions hashes:", hashes)
Now let's fetch a previously-broadcasted transaction:
tx_on_network = provider.get_transaction("09e3b68d39f3759913239b927c7feb9ac871c8877e76bc56e1be45a2a597eb53")
print("Status:", tx_on_network.status)
print("Is completed:", tx_on_network.is_completed)