What is Optimism?

Optimism is an optimistic rollup layer-2 network for Ethereum developed by OP Labs, one of the first major L2s to reach significant DeFi adoption. Its distinguishing architectural contribution is the OP Stack — a modular, open-source rollup framework that powers not only the Optimism mainnet (now called OP Mainnet) but also Coinbase's Base chain and dozens of other networks forming the Superchain. OP is the governance token used by the Optimism Collective's Token House.

The OP Stack's design philosophy separates rollup infrastructure into interchangeable modules (execution, settlement, consensus, data availability), allowing teams to deploy custom L2 chains — called OP Chains — that share security assumptions and eventually state-level interoperability with other Superchain members. Bedrock, the 2023 upgrade that formalized the OP Stack, reduced deposit times from 10 minutes to under 3 minutes and cut fees significantly by optimizing how calldata is packed. Optimism's Fault Proof system, deployed in 2024, replaced a trusted security council multisig with on-chain fraud proofs — a meaningful decentralization milestone that earlier versions lacked.

Optimism's governance model is intentionally bifurcated: the Token House (OP holders) votes on protocol upgrades and treasury allocations, while the Citizens House (soul-bound NFT holders) governs retroactive public goods funding (RetroPGF). This dual-house design is philosophically distinct from Arbitrum's DAO model, but critics note that Citizens House membership criteria and selection processes remain opaque, and that the Superchain's sequencer revenue sharing among OP Chains creates complex economic incentives that have not been fully stress-tested. Coinbase's operation of Base — the highest-revenue OP Chain — means a significant portion of Superchain economic activity flows through a single centralized company.

Reviewed by the 2Bitcoins Editorial Team · Updated June 2026. Not financial advice.