Arbitrum, created by the Offchain Labs team, is an Ethereum Layer2 scaling solution based on Optimistic Rollup technology. It leverages the ability to communicate between L1 and L2, allowing any form of Ethereum asset to be transferred between Layer 1 and Layer 2 without the need for trust. Even though Arbitrum transactions are still settled on Ethereum, only raw transaction data is submitted to Ethereum, with execution and contract storage occurring off-chain. This makes the gas fee required on Arbitrum much smaller than on the mainnet, and contracts are fully compatible with no gas limit.