Ethereum Layer2 solution? Comparison of Layer2 expansion technologies

Ethereum Layer2 solutions like rollups enhance scalability, reduce gas fees, and improve transaction speed while maintaining Ethereum's security.

Jun 16, 2025 at 02:15 pm

Understanding Ethereum Layer2 Solutions

Ethereum, as one of the most widely used blockchain platforms, has faced significant challenges regarding scalability and transaction speed. Layer2 solutions are protocols built on top of the Ethereum mainnet (Layer1) to enhance throughput and reduce costs. These solutions operate off-chain or semi-off-chain, handling transactions outside the primary blockchain while still leveraging Ethereum's security.

The core idea behind Layer2 scaling is to process transactions away from the congested Ethereum mainnet and batch them into a single transaction submitted to the main chain. This reduces gas fees and improves network efficiency. Popular Layer2 technologies include state channels, plasma, rollups (both optimistic and ZK-based).

Types of Ethereum Layer2 Scaling Technologies

There are several distinct approaches to Layer2 scaling, each with unique trade-offs in terms of security, decentralization, and performance:

• State Channels: These allow users to conduct multiple off-chain transactions before settling the final state on-chain. Examples include the Raiden Network. State channels offer fast and low-cost transactions, but require participants to be online and lock funds during the channel’s lifetime.

• Plasma: A framework for creating child blockchains anchored to the Ethereum mainnet. It uses fraud proofs to ensure validity. Plasma chains can handle thousands of transactions per second, but suffer from slower exit times and limited smart contract support.

• Rollups: The most promising category, rollups bundle multiple transactions into a single proof submitted to the mainnet. They fall into two subcategories:

  • Optimistic Rollups: Assume transactions are valid by default and only run computations if challenged. Projects like Arbitrum and Optimism use this model. They offer high compatibility with Ethereum Virtual Machine (EVM).
  • ZK-Rollups: Use zero-knowledge proofs to validate transactions instantly. zkSync and StarkNet are leading examples. They provide faster finality and stronger privacy guarantees, though EVM compatibility remains a challenge.

Comparing Performance Metrics

When evaluating Layer2 solutions, key metrics include throughput, latency, cost, security, and developer experience.

• Throughput: Plasma chains typically support hundreds to thousands of transactions per second. Rollups generally offer higher throughput, especially ZK-rollups, which can scale up to tens of thousands of TPS depending on implementation.

• Latency: State channels enable near-instant transactions. Plasma may take minutes to finalize exits. ZK-rollups have faster finality due to cryptographic proofs, whereas optimistic rollups require a challenge period (usually around 7 days).

• Cost: Gas fees on Layer2 networks are significantly lower than Layer1. However, ZK-rollups incur higher computational costs due to proof generation, making them more expensive per batch compared to optimistic rollups.

• Security: All Layer2 solutions inherit Ethereum’s base-layer security. However, ZK-rollups are considered more secure because they don’t rely on economic incentives to detect fraud, unlike optimistic rollups and plasma.

• Developer Experience: Optimistic rollups offer better EVM compatibility, allowing developers to deploy Solidity contracts with minimal changes. ZK-rollups often require specialized tooling and languages like Cairo or Zinc.

Use Cases and Adoption Trends

Each Layer2 solution caters to different use cases based on their technical characteristics.

• State Channels are ideal for micropayments and frequent peer-to-peer interactions, such as gaming or content monetization. However, they’re not suitable for open participation or complex smart contracts.

• Plasma works well for applications with predictable user behavior, like token transfers and simple DeFi functions. Their slow exit mechanism limits real-time interaction, making them less attractive for dynamic dApps.

• Optimistic Rollups are preferred for general-purpose DeFi and NFT platforms due to their EVM compatibility. Arbitrum and Optimism have seen widespread adoption among major protocols like Uniswap and Aave.

• ZK-Rollups are gaining traction in high-security environments such as exchanges and private transactions. StarkEx powers dYdX and Immutable X, offering scalable and confidential trading experiences.

Operational Setup: Deploying Smart Contracts on Layer2

Deploying a smart contract on Layer2 involves several steps that differ slightly depending on the specific technology used.

• Select a Layer2 Network: Choose between Arbitrum, Optimism, zkSync, or another supported platform. Ensure it aligns with your project’s requirements.

• Set Up Development Tools:

  • Install Truffle or Hardhat.
  • Add the Layer2 network configuration to hardhat.config.js or truffle-config.js.
  • Use compatible wallets like MetaMask and connect to the Layer2 provider (e.g., Alchemy or Infura for Arbitrum/Optimism).

• Compile and Deploy:

  • Compile the Solidity contract using solc or via Hardhat tasks.
  • Fund the wallet with test ETH or native tokens from the Layer2 faucet.
  • Run the deployment script pointing to the Layer2 RPC URL.

• Verify Contract:

  • Use block explorers like Arbiscan or Optimistic Etherscan.
  • Submit source code and compiler version for verification.

• Interact with dApp:

  • Update front-end providers to point to the Layer2 network.
  • Test transactions locally before going live.

This setup ensures smooth migration of existing Ethereum dApps to Layer2 environments without compromising functionality.

Frequently Asked Questions (FAQ)

Q: Can I move assets freely between Layer1 and Layer2?

Yes, most Layer2 networks provide bridges that allow bidirectional transfer of ETH and ERC-20 tokens. However, withdrawal periods vary depending on the solution—ZK-rollups offer faster exits than optimistic rollups.

Q: Are Layer2 solutions decentralized?

Most Layer2 protocols maintain decentralization principles, though some rely on centralized sequencers during early stages. Over time, projects aim to transition toward full decentralization through permissionless participation.

Q: Do all Layer2 solutions support NFT minting and trading?

While many do, ZK-rollups currently have limitations in supporting complex NFT logic due to EVM compatibility issues, whereas optimistic rollups are more flexible in this regard.

Q: How do Layer2 networks prevent malicious activity?

Fraud proofs and cryptographic validation mechanisms ensure integrity. In optimistic rollups, anyone can challenge invalid blocks within the dispute window, while ZK-rollups validate correctness upfront via SNARKs/STARKs.