Optimism, Start Here

Updated 2026-10-29

Short answer: Optimism (OP Mainnet) is an Ethereum layer 2 network: the same 0x addresses and apps as Ethereum, with lower fees paid in ETH. The OP token is used for governance. Its technology (the OP Stack) also runs other networks, including Base.

How it relates to Ethereum

Optimism processes transactions and posts them to Ethereum. ETH on Optimism, Ethereum and Base are separate balances, even with the same address.

Getting on and off Optimism

• Choose Optimism (sometimes "OP Mainnet") when you withdraw from an exchange.
• The official bridge back to Ethereum takes about seven days. See how crypto bridges work.
• Keep a little ETH on Optimism for fees.

Watch out

• Network names: Optimism, OP Mainnet and "OP" networks like Base share technology but are different networks.
• Fake OP airdrops and claim sites.
• Approvals: how to check and revoke token approvals.

On Crypto Lighthouse

• [Portfolio](/portfolio): your tokens on Optimism, DeFi positions and recent activity.
• [Approvals](/rewards): check and revoke, and claim Merkl incentive rewards.
• Token checks and [Check an Address](/check).

Learn more at optimism.io.