Layer 2 (L2)
By Menno — 13 years in crypto, 3 bear markets survived, zero paid promotions
Last updated: March 2026
A Layer 2 is a secondary blockchain built on top of a main chain (like Ethereum) to process transactions faster and cheaper. Popular L2s include Arbitrum, Optimism, and Base.
Layer 2 (L2) solutions are blockchains built on top of Layer 1 chains (like Ethereum) that handle transactions off the main chain while inheriting its security guarantees.
Why L2s exist: Ethereum's base layer can only process ~15-30 transactions per second, leading to high fees during congestion. L2s process transactions in bulk, then post compressed proofs back to Ethereum.
Types of L2s: - Optimistic rollups: assume transactions are valid, allow challenge period (Arbitrum, Optimism, Base) - ZK rollups: use cryptographic proofs to verify transactions (zkSync, StarkNet, Scroll)
Major L2 networks: - Arbitrum: largest L2 by TVL and activity - Base: Coinbase's L2, growing rapidly - Optimism: powers the OP Stack used by many chains - zkSync: leading ZK rollup
L2 benefits for users: - Fees: typically $0.01-$0.50 per transaction (vs $1-$50 on Ethereum) - Speed: faster confirmation times - Same security: inherits Ethereum's security guarantees - Full DeFi ecosystem: most major protocols deploy on L2s
For investors, L2 adoption is a bullish signal for Ethereum because L2s pay fees to Ethereum for data availability. Some L2s have their own tokens (ARB, OP) that may be investment opportunities.
Related Terms
Ethereum (ETH)
Ethereum is the second-largest cryptocurrency and the leading smart contract platform. It enables decentralized applications (dApps), DeFi protocols, and NFTs through programmable smart contracts.
Gas Fees
Gas fees are transaction costs paid to blockchain validators for processing transactions. Ethereum gas fees fluctuate based on network demand and can range from $0.50 to $100+ during peak congestion.
DeFi (Decentralized Finance)
DeFi is a category of financial services built on blockchain technology that operates without traditional intermediaries like banks. It includes lending, borrowing, trading, and earning yield through smart contracts.
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