Introduction
Ethereum Layer 2 (L2) solutions have emerged as a vital solution to Ethereum’s scalability challenges. By inheriting Ethereum’s security while offering low gas fees and high transaction throughput, L2 networks are reshaping blockchain efficiency. This article explores 15 Universal Rollup and Optimium projects, focusing on transaction fees and maximum achievable TPS (transactions per second).
Key Takeaways
- L2 Growth: Ethereum L2 solutions are rapidly expanding, handling over 60% of Ethereum transactions.
- Fee Structures: Rollup transaction fees consist of execution fees (L2 computation) and data fees (L1 calldata costs).
- Max TPS: Theoretical throughput varies significantly across projects due to batch intervals and compression techniques.
- Upcoming Upgrades: Ethereum’s EIP-4844 (Proto-Danksharding) will drastically reduce L2 data costs.
Understanding Layer 2 Scaling
The Rise of L2 Solutions
Since the launch of dYdX in 2019, L2 networks have grown exponentially. According to L2BEAT, daily L2 transactions now surpass Ethereum’s, with a scaling factor of 5.49x.
👉 Explore the latest L2 activity metrics
Rollup Technologies
Most L2 projects fall into two categories:
- Optimistic Rollups (ORU):
- Faster transaction finality but requires a 7-day fraud-proof window.
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Examples: Optimism, Arbitrum, Base.
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ZK Rollups (ZKR):
- Uses cryptographic proofs for instant finality but faces higher computation costs.
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Examples: zkSync Era, Starknet, Scroll.
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Optimiums:
- Sacrifices some decentralization for lower fees (e.g., Metis, Mantle).
Fee Structures in L2 Networks
Components of L2 Fees
- Execution Fee:
- Covers L2 computation (similar to Ethereum’s gas model).
-
Formula:
Execution Fee = Gas Used × Gas Price. -
Data Fee (Rollup Fee):
- Cost of storing transaction data on Ethereum (calldata).
- Dominates overall fees in most rollups.
Fee Comparison Across L2s
| Project | ETH Transfer Fee (USD) | ERC-20 Transfer Fee (USD) | Uniswap Swap Fee (USD) |
|---|---|---|---|
| Optimism | $0.10 | $0.15 | $0.30 |
| Arbitrum | $0.12 | $0.18 | $0.35 |
| zkSync Era | $0.25 | $0.30 | $0.50 |
| Starknet | $0.40 | $0.45 | $0.70 |
Note: Fees fluctuate based on L1 gas prices and network congestion.
Bridge Costs: Deposits & Withdrawals
Deposit Costs
- Cheapest: Base, Zora, Kroma (OP Stack-based).
- Most Expensive: Optimism, Arbitrum One (higher L1 interaction costs).
Withdrawal Costs
- Optimistic Rollups: Require fraud-proof windows (7 days).
- ZK Rollups: Faster but incur higher proof-generation costs.
| Project | Withdrawal Cost (USD) |
|---|---|
| Optimism | $5.00 |
| Arbitrum | $4.50 |
| zkSync Era | $3.00 |
Maximum TPS Analysis
Methodology
Max TPS is calculated as:
Max TPS = (Max # of L2 Transactions per Batch) / (Minimum Batch Interval)
Key Findings
| Project | Max TPS | Batch Interval | Compression Method |
|---|---|---|---|
| Optimism | 455 | 6 seconds | zlib |
| Arbitrum One | 226 | 10 seconds | Brotli |
| zkSync Era | 750 | 1 second | None |
| Starknet | 25 | 19 seconds | N/A |
Insight:
– zkSync Era leads in TPS due to minimal batch intervals.
– Starknet’s low TPS stems from high computational overhead in proof generation.
Future of L2 Scaling
EIP-4844 (Proto-Danksharding)
- Impact: Cuts L2 data costs by 10x.
- Timeline: Expected in 2024.
Sequencer Decentralization
- Goal: Improve censorship resistance and reliability.
- Challenges: Balancing decentralization with performance.
FAQs
Q1: Why are ZK Rollups more expensive than Optimistic Rollups?
A: ZKRs require cryptographic proof generation, which adds computational overhead.
Q2: How does EIP-4844 reduce L2 fees?
A: It introduces blob storage, lowering L1 data costs for rollups.
Q3: Which L2 has the fastest withdrawals?
A: ZK Rollups (e.g., zkSync Era) offer near-instant withdrawals.
Q4: Will L2s replace Ethereum?
A: No—L2s enhance Ethereum’s scalability while relying on its security.
Q5: How can developers optimize for L2 fees?
A: Use gas-efficient contracts and leverage L2-native toolkits (e.g., OP Stack).
Conclusion
L2 solutions are revolutionizing blockchain scalability, but fees and throughput vary widely across projects. With upcoming upgrades like EIP-4844, L2 networks will become even more cost-efficient.
About Kroma:
Kroma is an Optimistic Rollup with ZK fault proofs, built on OP Stack. Learn more at Kroma Network.