Optimism (OP) is a layer-two blockchain that operates on top of Ethereum, aiming to scale the Ethereum ecosystem by using optimistic rollups. This means transactions are recorded on Optimism but ultimately secured on Ethereum, benefiting from Ethereum's security. Optimism is home to numerous protocols and has a total value locked (TVL), making it a notable scaling solution for Ethereum. The Optimism Foundation, a nonprofit organization, leads Optimism with the goal of growing the Optimism ecosystem. The foundation is funded by donations and grants and strives to produce infrastructure that promotes the growth and sustainability of public goods.

Optimism operates with a focus on simplicity, pragmatism, and sustainability. It aims to keep its code as simple as possible, using proven Ethereum code and infrastructure when possible. The ecosystem is driven by the real-world needs and constraints of its team and users, aiming to build iteratively and implement features gradually. Optimism uses optimistic rollups and leverages the consensus mechanism of Ethereum to scale the network. Blocks are constructed and executed on Optimism (L2), while user transactions are batched up and submitted to Ethereum (L1). Transactions are submitted to Ethereum without direct proof of validity and can be challenged for a certain period of time. After this period, a transaction is considered final.

Optimism aims to create an ecosystem where value is generated for its three constituencies: token holders, contributors and builders, and users and community members. Token holders are compensated through the productive re-deployment of sequencer revenue. Contributors and builders receive value from retroactive public goods funding. Users and community members receive value from ongoing airdrops and project incentives. The demand for OP block space generates revenue, which is distributed to public goods, driving more demand for block space. This makes Optimism a potential platform for various decentralized applications and protocols.

Optimism is led by the Optimism Foundation, which is dedicated to growing the Optimism ecosystem. The foundation is completely funded by donations and grants and pledges to produce infrastructure that promotes the growth and sustainability of public goods. The foundation has set several milestones for the development of Optimism, including the introduction of Optimistic Rollup, the launch of the EVM Compatible Testnet, and the opening of the Mainnet. The foundation is working on decentralizing the sequencer and implementing next-generation fault proofing. The initial token supply of Optimism was 4,294,967,296 OP tokens, with a token generation rate of 2% per year.