This library works by injecting flashbots as a new module in the Web3.py instance, which allows submitting "bundles" of transactions directly to miners. This is done by also creating a middleware which captures calls to eth_sendBundle and eth_callBundle, and sends them to an RPC endpoint which you have specified, which corresponds to mev-geth.

To apply correct headers we use the flashbot method which injects the correct header on POST.

from eth_account.signers.local import LocalAccount
from web3 import Web3, HTTPProvider
from flashbots import flashbot
from eth_account.account import Account
import os

ETH_ACCOUNT_SIGNATURE: LocalAccount = Account.from_key(os.environ.get("ETH_SIGNER_KEY"))


w3 = Web3(HTTPProvider("http://localhost:8545"))
flashbot(w3, ETH_ACCOUNT_SIGNATURE)

Now the w3.flashbots.sendBundle method should be available to you. Look in examples/simple.py for usage examples.

To use goerli, add the goerli relay RPC to the flashbot function arguments.

flashbot(w3, ETH_ACCOUNT_SIGNATURE, "https://relay-goerli.flashbots.net")

Install poetry

Poetry will automatically fix your venv and all packages needed.

poetry install

Tips: PyCharm has a poetry plugin

See examples/simple.py for environment variable definitions.

poetry shell
ETH_SENDER_KEY=<sender_private_key> \
PROVIDER_URL=https://eth-goerli.alchemyapi.io/v2/<alchemy_key> \
ETH_SIGNER_KEY=<signer_private_key> \
python examples/simple.py

It's advisable to run black with default rules for linting

sudo pip install black # Black should be installed with a global entrypoint
black .