Optimistic Rollups are Ethereum Layer 2 solutions that is aiming to increase the scalability of the Ethereum blockchain. These solutions move transaction computations off-chain, but store transaction data to the Ethereum chain, which means that rollups are secured by Layer 1. Optimistic roll-ups are EVM compatible, meaning that they offer the full utility of the Ethereum network.
The two prominent projects that is competing in the Optimistic Rollups space are Optimism and Arbitrum. The two solutions are very similar, with the main difference being the way they generate fraud proof. There are also differences with regards to their compatibility with the Ethereum Virtual Machine (EVM) and Ethereum tooling.
The Trust Wallet Development Team is happy to announce that both Optimism and Arbitrum has been successfully integrated to the app. Update your app in iOS to version 6.6+ or Android version to 1.33+, to start utilizing these L2 scaling solutions.
Optimism uses a smart contract to relay transaction data from the main Ethereum chain to a Layer 2 network, where a sequencer can bundle multiple transactions into a batch and then submit that batch back to the main chain via a single transaction. Optimism tries to stick as close as possible to the Ethereum ecosystem. It uses a modified GETH for its Layer 2 node and it has a Solidity compiler. However, it does not support any EMV languages apart from Solidity.
Ethereum that is bridged to Optimism is represented by the token, Optimistic Ethereum (OETH) on Trust Wallet.
Learn more about Optimism here: https://optimism.io
Arbitrum is very similar to Optimism, with the main difference between the two projects being the way they generate fraud proof. Unlike Optimism, which executes the whole Layer 2 transaction, Arbitrum takes a multi-round approach where it executes small chunks of the L2 transaction until it finds a discrepancy. This approach has the benefit of enabling higher transaction capacity. Arbitrum supports all EMV languages, including YUL, Vyper and Solidity.
Ethereum that is bridged to Arbitrum is represented by the token, Arbitrum (ARETH) on Trust Wallet.
Learn more about Arbitrum here: https://arbitrum.io