The Ethereum scaling landscape is witnessing a new contender: based rollups. Introduced by Ethereum researcher Justin Drake in March 2023, based rollups aim to address key shortcomings of Optimistic and Zero-Knowledge (ZK) rollups—namely centralization risks, complexity, and high overhead—by moving transaction sequencing back to the base layer (L1). The concept has gained further traction after Vitalik Buterin announced on September 12, 2024, that starting next year he will only publicly mention Layer 2 solutions that have reached Stage 1+ maturity. This stance effectively puts based rollups in the spotlight as a potential standard for future Ethereum scaling.
From Traditional Rollups to Based Rollups
Rollups bundle multiple transactions, execute them off-chain on a Layer 2, and submit the compressed data back to Ethereum L1. Optimistic rollups assume transactions are valid by default and rely on fraud proofs, while ZK rollups use cryptographic proofs (SNARKs/STARKs) to verify correctness in one go. However, both types suffer from centralized sequencers that can lead to censorship, downtime, and extraction of maximum extractable value (MEV). The complexity of implementing custom sequencers and consensus mechanisms also increases development overhead.
Based rollups flip the script: instead of the L2 managing its own sequencer, all sequencing tasks are performed by the existing L1 infrastructure—searchers, builders, and proposers. This design is permissionless; anyone who can see the rollup’s mempool can participate in sequencing without needing to stake tokens or obtain approval. By eliminating the need for sequencer signature verification, based rollups achieve zero gas overhead, drastically reducing costs for users.
How Based Rollups Work
Based rollups are composed of four layers: consensus, data availability, execution, and settlement. The consensus, data availability, and settlement layers are all inherited from Ethereum L1; only the execution layer is handled by the rollup itself. The transaction lifecycle proceeds in four steps:
- L2 searchers bundle transactions occurring on the L2.
- L1 searchers and L2 block builders sequence these transactions into full L2 blocks.
- L1 searchers submit the full L2 blocks to L1 block builders.
- L1 proposers/validators include the L2 block data into L1 blocks, processing them like any other Ethereum transaction.
This collaborative mechanism ensures that every L2 block benefits from Ethereum’s security and uptime guarantees. Additionally, based rollups support pre-confirmations, allowing transactions to be provisionally confirmed before on-chain inclusion. Proposers face higher slashing penalties if they fail to honor pre-confirmation commitments, creating strong incentives for timely inclusion.
Pros and Cons of Based Rollups
The advantages are compelling: enhanced decentralization (anyone can sequence), high reliability (no single point of failure), reduced costs (no gas for sequencer verification), and simplicity (reuses existing L1 tech). However, there are trade-offs. The rollup itself does not capture the MEV revenue stream—it flows entirely to L1 participants. Sequencing flexibility is limited because the rollup cannot customize ordering rules; it must adhere to L1 block production dynamics. Scalability is also bounded by L1 capacity, as the L1 must process all rollup data and enforcement.
Despite these limitations, many developers argue the benefits outweigh the costs, especially for projects prioritizing security and decentralization over maximum customization.
Projects Building Based Rollups
Several teams are actively developing based rollup implementations. Notable projects include Taiko, Espresso, Fairblock, Sorella, and Chainbound. These teams are exploring different approaches to pre-confirmations, data availability, and incentive structures. Taiko, for instance, has already launched a testnet that demonstrates the core sequencing protocol.
Vitalik’s Vision for L2 Maturity
Vitalik Buterin’s recent tweet committing to only mention Stage 1+ L2s has sent a clear signal to the community: half-baked rollups with training wheels will no longer receive his endorsement. Stage 1+ indicates a rollup that has phased out centralized sequencer override capabilities and relies on a decentralized proof system. Based rollups naturally align with this vision because they inherit the decentralization of L1 from day one.
The competition among Optimistic, ZK, and based rollups is far from over. However, based rollups offer a path that is both technically elegant and ideologically aligned with Ethereum’s core values of decentralization and trust minimization. As the ecosystem matures, based rollups may well become the default choice for new L2 projects seeking a secure and simple scaling solution.