What is Layer 2?
Arbitrum, Optimism, zkSync and other scaling solutions, explained simply.
Why Layer 2 Exists
Ethereum (Layer 1) is secure but slow and expensive when congested. Layer 2 is a "second layer" built on top of Ethereum that processes many transactions off-chain and submits them back to the mainnet in batches — drastically cutting fees and boosting speed while inheriting mainnet security.
Main Types
Two mainstream approaches: Optimistic Rollups (like Arbitrum, Optimism) assume transactions are valid with a challenge window; ZK Rollups (like zkSync, StarkNet) use zero-knowledge proofs for instant verification. Both let users trade and use DeFi at far lower cost than mainnet.
What It Means for You
With Layer 2, you can transfer and trade for a few cents — instead of tens of dollars during mainnet peaks. Many exchanges support withdrawing directly to L2 networks like Arbitrum. Note: when bridging, always select the correct network, or you may lose funds.
