Ethereum competes with other chains like Solana or BNB Chain, thanks largely to its layer-2 solutions.
In fact, while the layer-1 of Solana and BNB Chain do not require layer-2 solutions due to their very fast and cost-effective transactions, Ethereum’s layer-1, on the other hand, needs layer-2 to compete on equal footing in these aspects.
The most important Ethereum layer-2 solutions are Arbitrum, Base, Optimism, Polygon, zkSync Era, and Starknet.
These are different solutions based either on easily implementable rollups or on secure and fast zero-knowledge (ZK) protocols.
Arbitrum
Arbitrum is the leading layer-2 of Ethereum for adoption and liquidity.
It was developed by Offchain Labs and has reached a DeFi TVL of approximately 3 billion dollars.
It is a 100% EVM-compatible layer-2, allowing developers to migrate dApps from Ethereum without needing to make any modifications.
Specifically, Arbitrum One handles up to 40,000 theoretical transactions per second, with a sustained average of 1,600 TPS and average costs of $0.08-0.10 per transaction. Arbitrum Nova, optimized for gaming and NFTs, further reduces costs to fractions of a cent.
On Arbitrum, there are already over 500 DeFi protocols hosted, such as Uniswap, Aave, and GMX, in addition to NFT marketplaces and games.
The main advantages are high liquidity, ease of development, and seamless integration with Ethereum. However, it is slightly slower compared to ZK-rollups.
Base
One of the most well-known layer-2 solutions is Base, as it was developed by the giant Coinbase.
This is an optimistic rollup launched in 2023, built on the OP Stack like Optimism, but managed independently.
Lately, it has surpassed Arbitrum in DeFi TVL, also thanks to its 4.2 million weekly active users.
It handles more transactions than any other layer-2 on Ethereum (up to 3.5 million per day), with average sustained TPS between 220–350.
The average fee per swap on Uniswap ranges between $0.04 and $0.07, making it very appealing.
With Coinbase backing it, it has experienced strong adoption, and given that it functions very well technically, it is likely to maintain strong usage.
The advantages of Base include extremely simple onboarding, extremely low and stable fees, as well as high liquidity on Aerodrome and direct integration with the Coinbase app.
However, it remains centralized in the sequencer, managed by Coinbase, and inherits any future vulnerabilities of the Optimistic Rollup.
Optimism
Optimism is a pioneer of optimistic rollups, as the project was founded in 2019.
In reality, it is not designed solely to scale Ethereum, but rather an entire “Superchain” of related chains, to facilitate interoperability.
It reaches a maximum of 2,500 TPS, with an average of 130 TPS and average fees of $0.12. The block time is 200 milliseconds, and it has processed a total of 2.47 billion transactions.
Over 200 dApps are running on Optimism, but its DeFi TVL has dropped significantly recently.
The advantages of Optimism are EVM compatibility, strong community support, and low entry-level costs.
However, it is less used and less liquid than Arbitrum.
Polygon
Polygon was one of the layer-2 solutions with the greatest potential.
It still has a DeFi TVL exceeding one billion dollars, but over time it has lost some ground to Arbitrum and Base.
Exceeds 65,000 theoretical TPS, with fees of only $0.01 and a confirmation time of 2.1 seconds. It supports both Proof-of-Stake and ZK-rollup for advanced security.
Hosts various dApps, with a particular emphasis on NFTs and gaming.
The main advantages are extreme scalability and interoperability with other chains, along with a mature ecosystem. However, it is somewhat more complex for basic users to navigate.
It is primarily used for gaming and NFTs, where volume matters more than immediate purpose.
zkSync Era
zkSync Era is the most revolutionary layer-2 on Ethereum.
Supports up to 20,000 TPS, but with fees less than a cent and finality in a few seconds thanks to SNARK proofs.
It already hosts over 200 dApps, with a particular emphasis on DeFi and payments.
It is primarily used for payments and privacy-focused apps, but it is also performing very well in terms of liquidity and cross-chain interoperability.
The advantages are rapid finality, extremely low transaction fees, and integrated privacy, but it is still not mature enough for complex dApps.
Starknet
Starknet achieves a theoretical throughput of millions of transactions per second thanks to STARK.
Currently, it has a maximum of 4,200 TPS, 2,600 sustained, fees of only $0.01, and instant finality. However, it is not fully EVM-compatible.
However, there are still not many dApps using it, so its ecosystem remains limited.
Its specific advantages are high efficiency for heavy computations and quantum-resistant security, but the Cairo language requires learning.
Starknet excels in advanced DeFi and AI-blockchain.
Which Layer-2 to Choose
Arbitrum and Optimism offer stability, Polygon versatility, and Starknet potential future developments.
In particular, Arbitrum and Base dominate in terms of general adoption, while Optimism leads for community and Polygon for volume. zkSync, on the other hand, excels in speed and Starknet in innovation.
In reality, the future of layer-2 for Ethereum is an interconnected ecosystem where layer-1 acts as a secure “settler,” and all can be used in an interconnected manner with each other.
It should be noted, however, that it is possible that ZK rollups like zkSync and Starknet could continue to chip away at the market share of optimistic rollups, thanks to instant finality and even lower costs.
However, it could be the “Superchain” of Optimism and Base to challenge Arbitrum’s dominance.
For retail traders or memecoin degens, the best choice might be Base.
For DeFi developers, Arbitrum is better.
For gaming or NFTs, there’s Polygon, while for privacy and instant payments, there’s zkSync Era.
Starknet remains for those who want to create very complex applications.