Layer 2

Crypto & Blockchain

Layer 2 (L2) networks are scaling solutions built on top of Layer 1 blockchains — processing transactions off-chain or in batches while inheriting L1 security. Major Ethereum L2s: Arbitrum, Optimism, Base (Coinbase's L2), Polygon zkEVM, zkSync. Categories: Optimistic Rollups (assume valid by default, fraud-prove if challenged — 7-day withdrawal delay) and Zero-Knowledge Rollups (mathematically prove validity — faster finality, more complex tech). L2 transaction fees: 10-100× cheaper than L1. Total Value Locked on L2s exceeds $30 billion. Bridging assets between L1 and L2 carries risk — past bridge hacks have lost billions. L2s have driven most of recent Ethereum activity growth.