Optimism is a layer 2 scaling solution for the Ethereum blockchain that aims to increase transaction throughput while reducing fees and latency. It uses optimistic rollups, a technique that allows off-chain processing of transactions before verifying them on the main chain, to achieve this goal.
Optimism also supports the Ethereum Virtual Machine (EVM), making it compatible with existing Ethereum smart contracts and tools. This enables developers to easily migrate their dApps to Optimism with minimal changes to their code. Overall, Optimism aims to improve the scalability and usability of Ethereum, making it more accessible to a wider range of users and use cases.