Fuel Labs announced that it has launched an open beta testnet for Fuel based on Optimistic Rollup's Ethereum sidechain, and the code is also open source. The Fuel sidechain is designed specifically for Ethereum's large-amount payment. Before the Istanbul upgrade, it is conservatively estimated that it can reduce Ethereum ERC-20 token transaction costs by 5 times. Fuel uses the UTXO data model, which can be easily verified by any computer or phone. The client can parallelize the verification and is browser-friendly.