Definition
Layer 2 (L2) — scaling technologies that work "on top" of the main blockchain (Layer 1). They process transactions off the main network, periodically recording results to L1.
Why Layer 2 is Needed
| L1 Problem |
L2 Solution |
| High fees |
Fees < $0.10 |
| Low speed |
Thousands of TPS |
| Network congestion |
Offload L1 |
Types of Layer 2
Optimistic Rollups
- How it works: Transactions assumed valid until proven otherwise
- Withdrawal period: 7 days (for challenges)
- Examples: Arbitrum, Optimism, Base
ZK Rollups
- How it works: Cryptographic proofs verify transactions
- Withdrawal period: Minutes
- Examples: zkSync, StarkNet, Scroll
Comparison
| Criteria |
Optimistic |
ZK Rollups |
| Fees |
Very low |
Low |
| Security |
High |
Very high |
| Withdrawals |
7 days |
Minutes |
| EVM compatibility |
Full |
Partial |
Popular L2 Networks
| Network |
TVL |
Features |
| Arbitrum |
$10B+ |
Largest L2, lots of DeFi |
| Optimism |
$5B+ |
OP Stack ecosystem |
| Base |
$3B+ |
Coinbase's L2 |
| zkSync |
$500M+ |
ZK technology |
How to Use Layer 2
Steps
- Add network to wallet (MetaMask)
- Transfer ETH via bridge
- Use DeFi applications on L2
- Withdraw to L1 when needed
Bridges
- Official network bridges
- Aggregators (Hop, Stargate)
- Exchanges (direct withdrawal to L2)
L2 and DCA
Layer 2 is perfect for DCA:
| Advantage |
Explanation |
| Low fees |
Can invest small amounts |
| Fast transactions |
Instant swaps |
| DeFi ecosystem |
Staking, farming |
Recommendations
- Withdraw from exchange directly to L2
- Use DEXs on L2 (Uniswap, GMX)
- Keep some ETH for gas
Layer 2 Risks
- Centralization — sequencers often centralized
- Bridges — vulnerable to hacks
- Novelty — technology still evolving
- Liquidity — less than on L1
Important: L2 inherits Ethereum security but adds its own risks. Choose proven networks with high TVL.
