Layer 2
Solutions built on top of a blockchain for faster, cheaper transactions.
Layer 2 (L2) are protocols built on top of Layer 1 blockchains (like Ethereum) to increase throughput and reduce costs, while inheriting the security of the parent chain.
Main L2 types:
•Optimistic Rollups — Arbitrum, Optimism, Base (Coinbase L2). Transactions are valid by default, but there's a challenge period.
•ZK Rollups — zkSync, Starknet, Scroll. Use cryptographic proofs for instant finality — technically more complex, but more secure.
Why L2:
•Ethereum mainnet: 15-30 TPS, gas fees $5-$50+
•Arbitrum/Base: 1000+ TPS, gas fees <$0.10
The L2 ecosystem exploded from 2023 — Coinbase Base, Linea, zkSync Era, Blast and dozens of others.