Ethereum on Arbitrum

ETH, the money of the Ethereum ecosystem, and on Arbitrum One the coin every transaction and contract call is paid for in: each fee covers the rollup's own execution plus the cost of publishing the transaction data to Ethereum. ETH arrives here through the canonical bridge, which locks it on Ethereum and credits it on Arbitrum, so a balance here is a claim on ETH held on the main chain. Arbitrum One is an optimistic rollup built by Offchain Labs, open to the public since August 2021.