Ethereum Layer 2 Guide: Rollups, Bridges and Choosing a Network
Arbitrum, Optimism, Base, zkSync, a practical guide to choosing and using Ethereum Layer 2 networks.
Why L2s exist
Ethereum mainnet prioritises decentralisation and security over throughput. Layer 2 networks batch transactions off-chain and post compressed proofs back to mainnet, inheriting Ethereum's security while offering 10x to 100x lower fees.
Optimistic vs ZK rollups
Optimistic rollups (Arbitrum, Optimism, Base) assume transactions are valid by default and rely on fraud proofs. ZK rollups (zkSync, StarkNet, Linea) use validity proofs that mathematically verify each batch. ZK is generally considered the long-term winning architecture; optimistic rollups currently have larger ecosystems.
How to bridge safely
Use canonical bridges where possible. Third-party bridges are convenient but introduce additional smart contract risk. Always check bridge contract addresses against the network's official documentation.
Funding an L2 from an exchange
Most major exchanges, including Bybit, support direct withdrawals to L2 networks such as Arbitrum and Optimism. This is usually cheaper and faster than withdrawing to mainnet and bridging separately.
Frequently asked questions
Are Layer 2s safe?
Mature rollups inherit much of Ethereum's security, but they are still newer systems with smart contract risk and varying degrees of decentralisation.
Which L2 has the lowest fees?
zkSync, Base and Linea typically have the lowest per-transaction costs, though they fluctuate with demand.
Do I need a different wallet for L2s?
No, any standard Ethereum wallet (MetaMask, Rabby, hardware wallets) works across L2s. You just need to add the network.
Can I withdraw from Bybit directly to an L2?
Yes. Bybit supports direct withdrawals to several Layer 2 networks.
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