This repo contains examples for using off-chain bundles, supported by the Merkle block builder. Off-chain bundles consists of both regular transactions and off-chain transactions. Off-chain transactions are objects that allow the block builder to initially construct and simulate a transaction off-chain. The return calldata of this simulation is used to construct and settle an on-chain transaction. To learn more about off-chain bundles refer to the official docs.
This example includes simple skeleton solidity contracts for using off-chain bundles and a demo application that creates and submits an off-chain bundle. Basic.sol demonstrates the use of a search() function that is simulated off-chain and a settle() function that is executed on-chain. BasicOnlySearch.sol and BasicOnlySettle.sol separate Basic.sol logic into a deployed contract and a contract passed in the off-chain transaction as bytecode. In this example BasicOnlySettle.sol is deployed and BasicOnlySearch.sol can be passed as bytecode. This allows for shielding strategy logic in the search contract and smaller deployed code size.
The app is a rust script that constructs off-chain bundles with and without the bytecode argument for the off-chain transaction.
Blind Backrun is an adaptation of the simple-blind-arbitrage example for blind backruns written by Flashbots. In this example the contracts have been updated and modified to separate the logic into an off-chain search component and an on-chain settle component similar to the Basic example. It demonstrates the massively reduced gas usage of the settle transaction that actually gets settled on-chain.
Install contract library dependencies.
$ forge install# build
$ FOUNDRY_PROFILE=basic forge build
# test
$ FOUNDRY_PROFILE=basic forge test
# run app
$ cd basic
$ cargo run# build
$ FOUNDRY_PROFILE=blind-backrun forge build —via-ir
# test
$ FOUNDRY_PROFILE=blind-backrun forge test —via-ir -f https://eth.merkle.io