Chapter 11

Major L2 Ecosystems

The L2 landscape is no longer experimental — billions of dollars in TVL and daily activity now live on rollups. Each major network made different choices about proof system, EVM compatibility, and ecosystem incentives, which shaped where developers and liquidity clustered.

Four rollups dominate Ethereum L2 activity, each with distinct strengths and tradeoffs.

Major L2 networks today

Network	Type	Notable trait
Arbitrum	Optimistic	Largest DeFi TVL, mature ecosystem
Base	Optimistic	Coinbase-backed, fast consumer app growth
Optimism	Optimistic	OP Stack, Superchain vision
zkSync	ZK	Native account abstraction, zkEVM

Liquidity and app availability vary by chain — always verify a protocol is deployed on your target L2 before bridging funds.

Arbitrum and Base lead in DeFi and general activity. Optimism pioneered the OP Stack — modular rollup software that powers Base and other chains in the Superchain. zkSync offers ZK-validity proofs with a focus on user experience through native account abstraction.

Starknet, Scroll, and other ZK rollups are growing, but the optimistic rollup trio plus zkSync currently capture most user attention. Ecosystem choice often comes down to where your preferred apps are deployed and which bridge paths are most liquid.