Blockchains

Ethereum Layer 2 Solutions Explained (2026): Arbitrum, Optimism, Base, zkSync

By HodlGuide Editorial Team · April 20, 2026 · 10 min read

Ethereum mainnet is expensive. During peak activity, a simple token swap can cost $20–$50 in gas fees, and more complex operations like adding liquidity or interacting with a lending protocol can cost hundreds of dollars. For most people, transacting directly on Ethereum mainnet is impractical.

Layer 2 networks solve this problem. They let you use the same Ethereum ecosystem — the same wallets, the same tokens, many of the same protocols — at a fraction of the cost. This guide explains how they work, compares the major options, and tells you which one to use for different purposes.

Why Layer 2 Exists

Ethereum’s design prioritises decentralisation and security over speed. Every transaction on Ethereum mainnet is processed by thousands of validators worldwide, each storing a full copy of the blockchain. This is what makes Ethereum tamper-proof and trustless. But it also means:

  • ~15–30 transactions per second — far below what’s needed for global adoption
  • High fees during congestion — when demand for block space exceeds supply, fees spike dramatically
  • Slow settlement — 12-second block times mean delays
  • Ethereum’s roadmap has always included a “rollup-centric” scaling strategy. Rather than trying to make Ethereum mainnet faster (which would require sacrificing decentralisation), the plan is to let Layer 2 networks handle the bulk of transactions while using Ethereum as a settlement and data availability layer.

    Layer 2s inherit Ethereum’s security. Your assets are ultimately backed by the Ethereum blockchain — not by a separate set of validators you have to trust.

    How Layer 2s Work: Rollups Explained

    All major Ethereum Layer 2s are rollups. A rollup:

    • Collects thousands of transactions from users
    • Executes those transactions off-chain (on the L2’s own infrastructure)
    • Compresses the results into a batch
    • Posts the batch data to Ethereum mainnet
    • Provides proof that the transactions were executed correctly

    Because data is compressed and batched, the cost per transaction is shared across thousands of users — hence the dramatically lower fees. But because the data is still posted to Ethereum, you retain Ethereum’s security guarantees.

    There are two types of rollups, and they differ in how they prove correctness:

    Optimistic Rollups

    Optimistic rollups assume all transactions are valid and post batches to Ethereum without immediate proof. Instead, there’s a challenge period (typically 7 days) during which anyone can submit a fraud proof if they detect an invalid transaction.

  • Pros: Easier to implement, fully EVM-compatible, mature ecosystem
  • Cons: 7-day withdrawal delay via official bridge, fraud proofs are complex to submit in practice
  • Examples: Arbitrum, Optimism, Base, Blast
  • The 7-day delay only applies to withdrawals to Ethereum mainnet via the official bridge. Deposits are fast (minutes), and third-party fast bridges can give you funds from L2 → Ethereum immediately for a small fee.

    ZK Rollups

    ZK rollups use zero-knowledge proofs — cryptographic mathematical proofs that allow one party to prove they know something (e.g., that all transactions are valid) without revealing the underlying data. Every batch posted to Ethereum includes a proof that the transactions were executed correctly.

  • Pros: Faster finality (no waiting for challenge period), mathematically provable security
  • Cons: More complex to build, historically harder to make fully EVM-compatible, higher computational cost for proof generation
  • Examples: zkSync Era, Polygon zkEVM, Starknet, Linea
  • ZK rollups are considered the long-term future of Ethereum scaling. The technology has matured significantly since 2023, with full EVM equivalence becoming achievable.

    Top Layer 2 Networks Compared

    Network Type TVL (approx.) Avg. Fee Ecosystem Focus Token
    Arbitrum One Optimistic rollup ~$3B+ $0.01–$0.15 DeFi ARB
    Base Optimistic rollup ~$2B+ $0.001–$0.05 Consumer, DeFi None*
    Optimism Optimistic rollup ~$1B $0.01–$0.10 DeFi, OP Superchain OP
    zkSync Era ZK rollup ~$500M+ $0.01–$0.05 General ZK
    Polygon zkEVM ZK rollup ~$100M+ $0.01–$0.05 General POL
    Starknet ZK rollup (STARK) ~$200M+ $0.01–$0.10 General STRK
    Blast Optimistic rollup ~$500M+ $0.01–$0.05 Yield, DeFi BLAST

    *Base has not launched a token as of 2026. This may change.

    TVL figures fluctuate with market conditions. Check L2Beat for current data.

    Arbitrum: The DeFi Powerhouse

    Arbitrum One consistently holds the highest TVL of any Ethereum L2. It was first to market with a production-grade optimistic rollup and benefited from early adoption by major DeFi protocols.

    Why Arbitrum leads in DeFi:

  • GMX — the dominant decentralised perpetuals exchange, with billions in open interest
  • Camelot DEX — the native Arbitrum DEX, designed for the ecosystem
  • Uniswap v3 — deep liquidity across all major pairs
  • Aave v3, Radiant Capital — lending markets
  • Pendle Finance — yield trading
  • The ARB token governs the protocol through the Arbitrum DAO, one of crypto’s largest DAOs by treasury size.

    Arbitrum Nova is a separate, cheaper Arbitrum chain using AnyTrust technology (data stored by a committee rather than posted to Ethereum). It’s used for gaming and high-frequency applications.

    Best for: Experienced DeFi users who want the deepest liquidity and most mature protocol ecosystem.

    Optimism and the OP Superchain

    Optimism launched shortly before Arbitrum and pioneered much of the optimistic rollup research. While it has slightly less TVL than Arbitrum in pure DeFi, its strategic significance is enormous: the OP Stack.

    The OP Stack is an open-source software framework for building L2 networks. Optimism open-sourced it and invited other chains to build on it, creating the OP Superchain — a network of interoperable L2s that share the same tech stack.

    OP Superchain chains include:

  • Base (Coinbase)
  • Optimism (OP Labs)
  • Mode Network
  • Zora (NFTs)
  • Redstone
    • And dozens more

    The vision: all these chains eventually share cross-chain messaging, liquidity, and security, making moving assets between them as seamless as transacting on a single network.

    Optimism’s DeFi ecosystem:

  • Velodrome — the dominant DEX on Optimism, using a vote-escrowed model
  • Synthetix — synthetic assets protocol, deeply integrated with Optimism
  • Aave v3 — lending market
  • Best for: Users who want exposure to the OP ecosystem and the OP token’s governance value.

    Base: Coinbase’s L2 and Fastest Growth

    Base is the L2 built by Coinbase using the OP Stack, launched in August 2023. It has grown faster than any L2 in history, driven by Coinbase’s massive user base and distribution advantages.

    Why Base is growing so fast:

    • Coinbase has tens of millions of users who can be onboarded to Base with minimal friction
    • Coinbase Wallet natively supports Base
    • Very low fees — often below $0.01 per transaction
  • The viral success of Friend.tech (2023–2024) brought mainstream attention
  • Aerodrome Finance became the dominant DEX with deep liquidity
  • Base’s unique position: It’s an institutional-grade, Coinbase-backed L2 that benefits from regulatory clarity (Coinbase is a publicly listed US company) and deep liquidity connections. It’s increasingly seen as the “default” L2 for new projects that want the broadest possible user reach.

    Base does not currently have a native token, which means there’s no token to earn from early use — though this may change.

    Best for: New crypto users coming from Coinbase, consumer apps, and developers who want access to Coinbase’s distribution.

    zkSync Era: Leading the ZK Revolution

    zkSync Era (developed by Matter Labs) is the leading ZK rollup by TVL and usage. It launched on mainnet in March 2023 and was one of the first ZK rollups to achieve full EVM compatibility, allowing Ethereum smart contracts to deploy without modification.

    ZK rollup advantages:

  • No 7-day withdrawal delay — ZK proofs allow faster finality
  • Mathematical security — proofs are verified by Ethereum, not subject to challenge games
  • Privacy potential — ZK technology opens the door to private transactions
  • zkSync Era ecosystem:

  • SyncSwap — leading DEX
  • Mute.io — DEX and yield aggregator
  • zkSync native protocols — various DeFi protocols launched natively
  • The ZK token was airdropped in June 2024 in one of the most controversial airdrops of the cycle — many eligible users felt the distribution was unfair. ZK is used for governance.

    Best for: Technical users who want to benefit from ZK security, developers building with ZK technology, and those who want fast finality without a challenge period.

    Polygon zkEVM

    Polygon zkEVM is Polygon’s ZK rollup, launched on mainnet in March 2023. It’s distinct from Polygon PoS (which is a sidechain) and represents Polygon’s bid for the future of ZK scaling.

    Polygon zkEVM is notable for being among the most EVM-equivalent ZK rollups — it can run existing Ethereum smart contracts with minimal changes, which makes it easy for developers to deploy. It uses the POL token and benefits from Polygon’s existing developer relationships.

    Best for: Developers already in the Polygon ecosystem who want ZK security guarantees.

    How to Use Layer 2 Networks

    Step 1: Add the Network to Your Wallet

    Every L2 needs to be added to your wallet manually (or via a tool like Chainlist).

    Network Chain ID RPC URL
    Arbitrum One 42161 https://arb1.arbitrum.io/rpc
    Optimism 10 https://mainnet.optimism.io
    Base 8453 https://mainnet.base.org
    zkSync Era 324 https://mainnet.era.zksync.io
    Polygon PoS 137 https://polygon-rpc.com

    Tip: Use chainlist.org to add any network to MetaMask with one click.

    Step 2: Bridge Assets from Ethereum

    For Arbitrum and Optimism: Use the official bridges (bridge.arbitrum.io, app.optimism.io/bridge) for maximum security. Use Across Protocol or Stargate for faster transfers.

    For Base: Use the official Base bridge (bridge.base.org) or Coinbase’s direct on/off ramp.

    For zkSync Era: Use the official zkSync bridge (portal.zksync.io) or third-party bridges.

    For all networks: Consider buying the native token (or ETH) directly on an exchange and withdrawing to the L2 address — often the simplest approach.

    Step 3: Get ETH for Gas

    All the major L2s use ETH for gas fees (except Polygon PoS which uses POL). You’ll need a small amount of ETH on each chain for transaction fees. $5–10 of ETH will cover many transactions.

    Realistic Fee Comparisons

    Action Ethereum Mainnet Arbitrum Base zkSync Era
    ETH transfer $2–$10 $0.05–$0.20 $0.01–$0.05 $0.05–$0.20
    Token swap (DEX) $10–$50 $0.10–$0.50 $0.02–$0.15 $0.10–$0.40
    Add liquidity $20–$100 $0.20–$1.00 $0.05–$0.25 $0.20–$0.80
    NFT mint $20–$200 $0.20–$2.00 $0.05–$0.50 $0.20–$1.00

    Fees vary significantly with network congestion and ETH price. These ranges reflect typical conditions in 2025–2026.

    Which Layer 2 Should You Use?

    For DeFi (experienced users): Start with Arbitrum One — it has the deepest liquidity, most mature protocols, and the widest selection of DeFi strategies.

    For beginners / coming from Coinbase: Base is the easiest entry point, especially if you already use Coinbase. Very low fees and a growing ecosystem.

    For gaming and social apps: Base or Arbitrum Nova — ultra-low fees for frequent small transactions.

    For maximum security / ZK fans: zkSync Era or Polygon zkEVM — faster finality and cryptographic proof of validity.

    For Ethereum ecosystem exposure overall: Many users maintain wallets on multiple L2s. The cost of being on multiple chains is just the bridging fee — after that, transactions are cheap on all of them.

    Frequently Asked Questions

    Are my funds safe on Layer 2?

    L2s inherit Ethereum’s security for the network layer — your assets are backed by Ethereum consensus. The risk factors to consider are: smart contract risk in the DeFi protocols you use, sequencer centralisation (all major L2s currently have centralised sequencers), and bridge security. Bridge exploits have been a significant source of losses in crypto. Use audited bridges and understand what you’re doing before moving large amounts.

    Can I lose my money on a Layer 2?

    The L2 infrastructure itself is unlikely to cause losses — it’s secured by Ethereum. The risks come from the DeFi protocols built on top of L2s, which can have vulnerabilities, or from phishing attacks where you’re tricked into approving malicious transactions. Use hardware wallets for significant amounts.

    Which L2 has the most users?

    Base and Arbitrum consistently compete for the top spot in daily active addresses. Base benefits from Coinbase’s distribution. Arbitrum has the larger DeFi user base by TVL. This varies with market conditions and viral moments.

    Do I need a different wallet for each L2?

    No. The same Ethereum wallet address (e.g., your MetaMask wallet) works across all EVM-compatible L2s. You just switch the network in your wallet. Your address is the same on Ethereum, Arbitrum, Optimism, Base, and Polygon.

    Will there eventually be one dominant L2?

    Most analysts expect the L2 landscape to have 2–3 major ecosystems alongside dozens of application-specific chains. The OP Superchain (Base + Optimism + others) and Arbitrum are the two dominant ecosystems today. ZK technology may reshape rankings over time as it matures.

    What is L2Beat?
    L2Beat is the essential resource for L2 research. It tracks TVL, security properties, risk ratings, and technical details for every major L2. Bookmark it if you spend time in the L2 ecosystem.

    What’s the difference between a rollup and a sidechain?

    A rollup posts transaction data to Ethereum and derives its security from Ethereum consensus. A sidechain (like Polygon PoS) has its own validators and only posts periodic checkpoints to Ethereum — it doesn’t inherit Ethereum’s full security for every transaction. Rollups are generally considered more secure.


    Related guides:

  • What is Arbitrum? The Complete Guide (2026)
  • What is Polygon (POL)? Complete Guide (2026)
  • How to Add Arbitrum to MetaMask
  • How to Add Optimism to MetaMask