Beyond ZK & Optimistic Rollups: Introducing Based Rollups and Preconfirmations

Ethereum’s scalability landscape has long been defined by Optimistic Rollups and ZK-Rollups, but a new approach is emerging: Based Rollups. These rollups aim to enhance decentralization by leveraging Ethereum’s existing block builder network, removing the need for centralized sequencers.

This blog explores what Based Rollups are, how they work, their advantages over traditional rollups, and how pre-confirmations can help them compete with faster rollup architectures.

What Are Based Rollups?

Ethereum introduced Layer-2 (L2) rollups to increase transaction throughput and lower gas fees by executing transactions off-chain while storing their state on Ethereum. Traditional rollups require a sequencer—a centralized server that orders transactions before submitting them to Ethereum. While these rollups benefit from Ethereum’s security, centralized sequencers create a single point of failure and censorship risk.

Based Rollups remove this centralization risk by using Ethereum’s block builders instead of independent sequencers. By integrating directly with Ethereum’s proposer-builder separation (PBS) model, Based Rollups achieve greater decentralization without introducing new centralized components.

Ethereum’s Proposer-Builder Separation (PBS)

Ethereum’s Proof-of-Stake (PoS) model divides block production into two roles:

• Block Builders: Construct blocks by selecting transactions and optimizing for MEV (Maximal Extractable Value).
• Proposers (Validators): Validate and append blocks to the Ethereum blockchain.

Based Rollups integrate into this system by allowing Ethereum’s block builders to act as rollup sequencers. This approach provides:

? Decentralization – No need for a separate, centralized sequencer. Ethereum’s validators oversee the process, making attacks more difficult.

? Censorship Resistance – Since multiple builders compete to produce blocks, transaction ordering is less susceptible to manipulation.

How Based Rollups Leverage Ethereum’s Builder Network

By allowing Ethereum’s block builders to sequence transactions, Based Rollups eliminate the need for external sequencers. This means:

• No additional infrastructure is required for transaction ordering.
• Ethereum’s decentralized builder network ensures that no single entity controls rollup sequencing.
• Security is fully inherited from Ethereum, providing stronger guarantees than standalone rollups.

Ethereum builders essentially become the sequencers for Based Rollups, increasing decentralization while maintaining scalability.

Advantages of Based Rollups

Like traditional rollups, Based Rollups offer significant fee reductions—up to 100x lower gas costs compared to Ethereum mainnet. However, they introduce additional benefits:

? Decentralization – No reliance on a single sequencer; Ethereum’s builder network ensures censorship resistance.

? Shared Liquidity with Ethereum – Unlike rollups that fragment liquidity, Based Rollups can share state and liquidity directly with Ethereum and other Based Rollups, allowing atomic swaps and cross-chain interoperability.

DEXs like Uniswap can execute transactions across Ethereum and Based Rollups without liquidity fragmentation, a capability currently seen only in OP Superchain, Arbitrum Orbit, and zkSync Elastic Chains.

Preconfirmations (Preconfs): Solving the Block Time Challenge

One challenge facing Based Rollups is Ethereum’s 12-second block time. Traditional rollups like Arbitrum and Optimism process transactions every 200ms–1s, making them significantly faster. Since Based Rollups rely on Ethereum’s block builders, they inherit Ethereum’s block production delays, which could make them less attractive for high-speed trading.

Pre-confirmations address this issue by introducing sub-blocks within each Ethereum block. This enables Based Rollups to:

• Reduce transaction latency for DeFi applications.
• Improve execution speeds (200ms–1s), matching other rollups.
• Enhance cross-rollup transactions without excessive delays.

However, pre-confirmations introduce complexity, particularly for shared liquidity models where rollups and Ethereum interact simultaneously. The challenge lies in balancing speed, liquidity, and security to ensure seamless execution.

State of Based Rollups

The first Based Rollup, Taiko, is already live, with more projects in development. Pre-confirmation models are actively being researched, and their impact on Based Rollups could be game-changing.

Ethereum researcher Jake Dahn predicts that major rollups like Arbitrum, Optimism, and zkSync may eventually adopt Based Rollup architectures. If this transition happens, centralized sequencers could become obsolete, further decentralizing Ethereum’s Layer-2 ecosystem.

Based Rollups in the Institutional Adoption

Beyond DeFi applications, Based Rollups could revolutionize institutional blockchain adoption. Global financial organizations like BIS (Bank for International Settlements) and MAS (Monetary Authority of Singapore) are exploring Layer-1 blockchain solutions for financial markets. Currently, they rely on Ethereum for settlement, but a Based Rollup model could provide a more efficient alternative with built-in privacy and compliance controls.

However, this model is a double-edged sword. Centralized sequencers do provide advantages, particularly for financial institutions that need transaction control based on KYC/AML requirements. While Based Rollups enhance decentralization, centralized sequencers may still hold value for regulated industries.

Conclusion

Based Rollups offer a compelling alternative to traditional rollups by eliminating centralized sequencers, enhancing Ethereum’s decentralization, and enabling shared liquidity across the Ethereum network. However, their success depends on solving block production time limitations, which pre-confirmations aim to address.

As Ethereum’s Layer-2 ecosystem evolves, Based Rollups could become the next major innovation, challenging existing rollup models. Whether Arbitrum, Optimism, and zkSync adopt this architecture remains uncertain, but the future of Ethereum scalability is being redefined in real-time.

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