Ethereum Layer 2s

What You Probably Got Wrong

L2 costs: You think $0.01-2.00 per transaction. Reality: $0.001-0.003 for swaps, $0.0003 for transfers. After EIP-4844, L2 batch costs dropped from $50-500 to $0.01-0.50.

Mainnet is cheap too: At 0.05 gwei, mainnet ETH transfers cost $0.002. "Ethereum is too expensive" is false for both L1 and L2s in 2026.

Base is the cheapest major L2: Often 50% cheaper than Arbitrum/Optimism. Direct Coinbase on-ramp. Fastest-growing L2 with consumer/AI agent focus.

L2 Comparison Table (Feb 2026)

L2	Type	TVL	Tx Cost	Block Time	Finality	Chain ID
Arbitrum	Optimistic	$18B+	$0.001-0.003	250ms	7 days	42161
Base	Optimistic	$12B+	$0.0008-0.002	2s	7 days	8453
Optimism	Optimistic	$8B+	$0.001-0.003	2s	7 days	10
Linea	ZK	$900M+	$0.003-0.006	2s	30-60min	59144
zkSync Era	ZK	$800M+	$0.003-0.008	1s	15-60min	324
Scroll	ZK	$250M+	$0.002-0.005	3s	30-120min	534352
Polygon zkEVM	ZK	$150M+	$0.002-0.005	2s	30-60min	1101

Mainnet for comparison: $50B+ TVL, $0.002-0.01, 8s blocks, instant finality.

Cost Comparison (Real Examples, Feb 2026)

Action	Mainnet	Arbitrum	Base	zkSync	Scroll
ETH transfer	$0.002	$0.0003	$0.0003	$0.0005	$0.0004
Uniswap swap	$0.015	$0.003	$0.002	$0.005	$0.004
NFT mint	$0.015	$0.002	$0.002	$0.004	$0.003
ERC-20 deploy	$0.118	$0.020	$0.018	$0.040	$0.030

Quick L2 Selection Guide

Need	Choose	Why
Cheapest gas	Base	~50% cheaper than Arbitrum/Optimism
Deepest DeFi liquidity	Arbitrum	$18B TVL, most protocols
Coinbase users	Base	Direct on-ramp, free Coinbase→Base
No 7-day withdrawal wait	ZK rollup (zkSync, Scroll, Linea)	15-120 min
AI agents / social apps	Base	ERC-8004, Farcaster, consumer ecosystem
Superchain ecosystem	Optimism or Base	OP Stack, shared infra
Maximum EVM compatibility	Scroll or Arbitrum	Bytecode-identical

The Superchain (OP Stack)

You probably know OP Stack basics. Key update: Superchain Interop (coming 2026) enables cross-chain calls between OP Stack L2s (Optimism, Base, Zora, Mode, 50+ more). Fast native bridging is ~1-2 min between members.

Deployment Differences (Gotchas)

Optimistic Rollups (Arbitrum, Optimism, Base)

✅ Deploy like mainnet — just change RPC URL and chain ID. No code changes.

Gotchas:

•Don't use block.number for time-based logic (increments at different rates). Use block.timestamp.
•Arbitrum's block.number returns L1 block number, not L2.

ZK Rollups

•zkSync Era: Must use zksolc compiler. Some opcodes not supported (SELFDESTRUCT, CALLCODE). Native account abstraction (all accounts are smart contracts).
•Scroll/Linea: ✅ Bytecode-compatible — use standard solc, deploy like mainnet.

RPCs and Explorers

L2	RPC	Explorer
Arbitrum	`https://arb1.arbitrum.io/rpc`	https://arbiscan.io
Base	`https://mainnet.base.org`	https://basescan.org
Optimism	`https://mainnet.optimism.io`	https://optimistic.etherscan.io
zkSync	`https://mainnet.era.zksync.io`	https://explorer.zksync.io
Scroll	`https://rpc.scroll.io`	https://scrollscan.com
Linea	`https://rpc.linea.build`	https://lineascan.build

Bridging

Official Bridges

L2	Bridge URL	L1→L2	L2→L1
Arbitrum	https://bridge.arbitrum.io	~10-15 min	~7 days
Base	https://bridge.base.org	~10-15 min	~7 days
Optimism	https://app.optimism.io/bridge	~10-15 min	~7 days
zkSync	https://bridge.zksync.io	~15-30 min	~15-60 min
Scroll	https://scroll.io/bridge	~15-30 min	~30-120 min

Fast Bridges (Instant Withdrawals)

•Across Protocol (https://across.to) — fastest (30s-2min), lowest fees (0.05-0.3%)
•Hop Protocol (https://hop.exchange) — established, 0.1-0.5% fees
•Stargate (https://stargate.finance) — LayerZero-based, 10+ chains

Security: Use official bridges for large amounts (>$100K). Fast bridges add trust assumptions.

Multi-Chain Deployment (Same Address)

Use CREATE2 for deterministic addresses across chains:

bash

# Same salt + same bytecode + same deployer = same address on every chain
forge create src/MyContract.sol:MyContract \
  --rpc-url https://mainnet.base.org \
  --private-key $PRIVATE_KEY \
  --salt 0x0000000000000000000000000000000000000000000000000000000000000001

Strategy for new projects: Start with 1 L2 (Base or Arbitrum). Prove product-market fit. Expand with CREATE2 for consistent addresses.

Testnets

L2	Testnet	Chain ID	Faucet
Arbitrum	Sepolia	421614	https://faucet.arbitrum.io
Base	Sepolia	84532	https://faucet.quicknode.com/base/sepolia
Optimism	Sepolia	11155420	https://faucet.optimism.io

l2s