Definition
Optimism is a Layer 2 network built on top of Ethereum that aims to make transactions faster and cheaper while still relying on Ethereum for security. It uses a rollup approach, where many individual transactions are bundled together and then submitted to Ethereum as a single, compressed update. This design allows Optimism to handle more activity than the Ethereum base layer alone, reducing congestion and costs. As a concept, Optimism refers both to the specific Layer 2 network and to its optimistic rollup model for scaling Ethereum.
In Optimism’s architecture, a component called a sequencer orders transactions and produces batches that are later recorded on Ethereum. The system assumes transactions are valid by default, and relies on a dispute mechanism to handle incorrect or fraudulent data. By anchoring its state and data to Ethereum, Optimism inherits the underlying security of the main chain while operating most activity off-chain. This makes it a prominent example of how rollup-based Layer 2 designs extend Ethereum’s capacity without changing its core protocol.
Context and Usage
Optimism is commonly described as an optimistic rollup, a specific type of rollup that trusts submitted transaction batches unless they are challenged. In the broader Ethereum ecosystem, it is grouped with other Layer 2 solutions that move execution off the main chain but keep settlement and data availability on Ethereum. The term is often used when discussing how Ethereum can scale to support more users and applications without sacrificing decentralization.
Because Optimism is closely tied to Ethereum, it is frequently mentioned in relation to concepts like the sequencer that manages transaction ordering and the rollup mechanism that compresses data. References to Optimism usually focus on its role as a scaling layer rather than as a separate, independent blockchain. In educational and technical contexts, it serves as a key example of how Layer 2 designs can expand blockchain capacity while maintaining a strong connection to an existing base network.