Contains smart contract suite to enable instant token transfers between any two networks. Relays are backstopped by liquidity held in a central HubPool on Ethereum, which also serves as the cross-chain administrator of all contracts in the system. SpokePool contracts are deployed to any network that wants to originate token deposits or be the final destination for token transfers, and they are all governed by the HubPool on Ethereum.

This contract set is the second iteration of the Across smart contracts which facilitate token transfers from any L2 to L1.

These contracts were audited by OpenZeppelin which is a great resource for understanding the contracts.

This video is also useful for understanding the technical architecture.

Build

yarn
yarn hardhat compile

Test

yarn test # Run unit tests without gas analysis
yarn test:gas-analytics # Run only tests that count gas costs
yarn test:report-gas # Run unit tests with hardhat-gas-reporter enabled

Lint

yarn lint
yarn lint-fix

Deploy and Verify

NODE_URL_1=https://mainnet.infura.com/xxx yarn hardhat deploy --tags HubPool --network mainnet
ETHERSCAN_API_KEY=XXX yarn hardhat etherscan-verify --network mainnet --license AGPL-3.0 --force-license --solc-input

ZK Sync Adapter

These are special instructions for compiling and deploying contracts on zksync. The compile command will create artifacts-zk and cache-zk directories.

Compile

This step requires Docker Desktop to be running, as the solc docker image is fetched as a prerequisite.

yarn compile-zksync