L2 for Ethereum: Why Arbitrum, Base, and Optimism Matter

Ethereum, especially during periods of high congestion, makes even a simple transaction expensive. At the 2021 peak, a token swap cost $200; at the 2024 peak, it was $40–80. L2 networks solve this problem through different technical approaches but with a single goal: make transactions cheaper without sacrificing security.

How It Works in a Nutshell

L2 is a separate network with its own blocks and validators, but it derives its security from the Ethereum mainnet: it periodically sends a summary proof (rollup) of all its transactions to Ethereum. If someone tried to cheat, the proof would be refuted, and the L2 operators would be economically penalized.

There are two main types:

• Optimistic rollups (Arbitrum, Optimism, Base) – trust operators by default but provide a window for dispute (7 days). Cheaper, but withdrawing back to Ethereum takes a week.
• ZK-rollups (zkSync, Starknet, Polygon zkEVM) – each rollup is accompanied by a mathematical proof of correctness. More computationally expensive, but withdrawals are nearly instant.

Which Network to Choose in Practice

Arbitrum – the largest in terms of liquidity and number of protocols. If you want DeFi, go here.

Base – L2 from Coinbase. Convenient fiat onramp via Coinbase card, cheap gas, easy wallet integration. For beginners, this is often the most comfortable path.

Optimism – similar to Arbitrum but with its own OP airdrop and an active ecosystem of social projects.

USDT/USDC move freely across all three networks. Most exchanges support deposits and withdrawals on Arbitrum, and many on Base.

What to Watch Out For

When withdrawing from a CEX, select the correct network: if you choose Ethereum, the transfer will take time and be expensive; if you choose Arbitrum, it will be cheap and fast. If you mix up the network, funds may be lost. This is especially important when sending to a contract address on a DEX, not to a regular wallet.

Bridges (Stargate, Hop, Across) are services for moving between L2 and mainnet. Use only official links. Fake bridge sites are one of the most common types of phishing in 2024–2026.