Ethereum’s long-running scaling race has produced a wide range of Layer 2 architectures, but roll-ups remain the dominant framework for expanding throughput while preserving the security of the base chain. A newer design, known as the based roll-up, is now drawing attention as a potentially important next step in that evolution.
The idea is straightforward but significant: instead of relying on a dedicated Layer 2 sequencer to order transactions, based roll-ups move that function closer to Ethereum itself. By using Ethereum Layer 1 infrastructure for sequencing, proponents argue that the model can improve decentralization, reliability, and simplicity compared with more established roll-up designs.
Why Roll-Ups Became Central to Ethereum Scaling
Ethereum has long offered strong security and a rich smart contract environment, but those advantages have come with a familiar drawback: high fees and limited throughput on the base layer. Roll-ups emerged as a response to that problem. Their basic model is to process or execute transactions away from the main chain, bundle them together, and then post the resulting data or proofs back to Ethereum Layer 1.
This design reduces congestion on the base chain while still inheriting important parts of Ethereum’s security model. Over time, two major categories came to dominate the discussion: optimistic roll-ups and zero-knowledge roll-ups.
Optimistic roll-ups assume transactions are valid by default and only challenge them when fraud is suspected. This avoids constant heavy verification on Layer 1, but it also creates a delay window for dispute resolution, which can result in slower withdrawals and longer finalization periods.
ZK roll-ups take a different path. They batch transactions off-chain and return them to Ethereum with a cryptographic validity proof, typically using technologies such as SNARKs or STARKs. Because the proof demonstrates the correctness of the state transition, Ethereum does not need to redo the underlying computation. That can enable faster validation and higher throughput, though the systems involved are often technically complex.
Despite their differences, both major roll-up models share an important concern: sequencing. Whoever controls the ordering of transactions can affect fairness, censorship resistance, uptime, and the overall decentralization profile of the system. That is the opening based roll-ups aim to address.
What Makes a Roll-Up “Based”
The concept of based roll-ups was introduced in March 2023 by Ethereum researcher Justin Drake. The defining feature is that sequencing happens on the base layer, rather than being handled by an external Layer 2 sequencer controlled by the roll-up itself.
In practice, that means based roll-ups seek to leverage Ethereum’s existing block production ecosystem, including searchers, builders, and proposers, to perform sequencing tasks. Instead of building a separate and potentially centralized ordering system at the Layer 2 level, the roll-up leans on infrastructure that already exists on Ethereum.
Supporters of the model argue that this approach can create a more permissionless environment. Anyone able to observe the roll-up mempool can potentially participate in sequencing-related activity, rather than needing access to a privileged operator or token-based governance system. That design, in theory, strengthens decentralization while also reducing operational complexity.
Architecture and Transaction Flow
Based roll-ups are typically described through four layers: the consensus layer, the data availability layer, the execution layer, and the settlement layer. In this framework, Ethereum Layer 1 provides the consensus, data availability, and settlement functions, while the roll-up itself primarily handles execution.
The transaction lifecycle can be understood as a multi-step collaborative process. First, Layer 2 searchers gather and bundle user transactions. Second, Layer 1 searchers and Layer 2 builders work together to sequence those transactions into full Layer 2 blocks. Third, Layer 1 searchers submit those completed Layer 2 blocks to Layer 1 block builders. Finally, Layer 1 block builders include the Layer 2 data in Layer 1 blocks, which are then processed by Ethereum validators like any other transaction data on the network.
This sequencing model is intended to be permissionless. In other words, adding roll-up blocks to Layer 1 should not depend on special access rights granted by a centralized sequencer. By embedding the process into Ethereum’s own block production pipeline, based roll-ups aim to preserve the chain’s security assumptions and uptime characteristics while lowering the complexity that comes with custom sequencing systems.
Pre-Confirmations and User Experience
One of the notable design advantages highlighted for based roll-ups is the use of pre-confirmations. These allow transactions to receive an early assurance before they are formally included on-chain. For users, that can translate into a faster and smoother experience, especially in applications where waiting for final inclusion can create friction.
However, pre-confirmations are not free. They require proposers to accept stronger slashing risk. If a proposer promises inclusion through a pre-confirmation and then fails to deliver that transaction on-chain as expected, the penalties can be higher. That stronger enforcement mechanism is intended to make early assurances credible, rather than merely aspirational.
In the broader Ethereum user experience discussion, this is important. A roll-up architecture that combines lower cost, inherited security, and faster practical confirmation could become attractive not only to developers but also to users who increasingly expect centralized-exchange-like responsiveness without giving up the benefits of decentralized infrastructure.
The Main Benefits
The case for based roll-ups rests on several clear advantages. First is greater decentralization. By shifting sequencing to Ethereum Layer 1 infrastructure, the architecture reduces reliance on a single Layer 2 operator or tightly controlled sequencer set.
Second is reliability. Because the model depends more directly on Ethereum’s existing validator and block-building environment, it may reduce the downtime and liveness risks associated with standalone sequencer systems.
Third is cost efficiency. The design aims to remove the gas overhead tied to sequencer signature verification and related coordination steps, creating a lower-cost operational model for transaction ordering and submission.
Fourth is simplicity. Rather than reproducing a full sequencing and consensus apparatus at the Layer 2 level, based roll-ups reuse the machinery already present on Ethereum. For builders, that can lower implementation complexity and reduce the number of moving parts they need to secure and maintain.
The Trade-Offs and Limitations
Like every scaling design, based roll-ups come with trade-offs. One of the most important is economic. A roll-up that does not run its own sequencer may not capture the same MEV revenue opportunity that more vertically integrated optimistic or ZK roll-ups might capture. Instead, that value may accrue more directly to Layer 1 participants, since sequencing is taking place there.
Another limitation is reduced flexibility. Dedicated sequencer designs give roll-up teams more room to customize transaction ordering, confirmation behavior, and optimization strategies. By comparison, a based roll-up is more tightly constrained by what Ethereum Layer 1 allows and how its own sequencing pipeline evolves over time.
That means part of the roll-up’s future performance is tied to the base layer’s architecture and scalability path. Builders working outside the core Ethereum block production flow may have fewer opportunities to redesign sequencing for specialized use cases or maximum efficiency. In exchange for simplicity and decentralization, they may give up a degree of control.
Where Based Roll-Ups Fit in the Current Ethereum Landscape
The Ethereum Layer 2 sector is still highly competitive. At present, optimistic roll-ups remain dominant in market visibility and usage, and the article notes that Arbitrum and Optimism are among the projects that have reached the Stage 1 threshold emphasized by Vitalik Buterin.
Vitalik has said that starting the following year, he plans to publicly mention only Layer 2s that are Stage 1+, with only limited flexibility for genuinely new and interesting projects. That stance reflects a maturing standard for Ethereum scaling: projects are increasingly expected to demonstrate stronger security assumptions, reduced reliance on training wheels, and a clearer path toward robust decentralization.
Within that environment, based roll-ups are being framed as an attempt to take some of the practical strengths associated with optimistic systems while improving transaction sequencing through a more decentralized model. The resulting architecture is not necessarily a replacement for all other roll-up designs, but rather a new point in the design space.
Projects Exploring the Model
The article points to several names associated with this emerging area, including Taiko, Espresso, Fairblock, Sorella, and Chainbound. These projects are exploring different pieces of the based roll-up stack or adjacent infrastructure needed to make the model practical.
That list also underscores an important reality: based roll-ups are still best understood as an active area of development rather than a finalized winner in the Layer 2 race. Their future importance will depend on whether teams can translate the theory into production systems that deliver meaningful user adoption, stable economics, and competitive developer experience.
Final Take
Based roll-ups represent one of the more interesting ideas in Ethereum’s ongoing search for scalable yet credibly decentralized infrastructure. By moving sequencing closer to Ethereum Layer 1, they promise a design that is simpler, more decentralized, and potentially more reliable than traditional roll-up architectures built around dedicated sequencers.
At the same time, those gains come with meaningful constraints, especially around MEV capture, design flexibility, and dependence on Ethereum’s own limits. Whether the trade-off is worth it will depend on what developers and users value most.
For now, based roll-ups should be viewed as an important experiment in Ethereum’s Layer 2 evolution. If they can prove that lower complexity and stronger alignment with Layer 1 can coexist with strong performance and good user experience, they may become a major force in the next phase of Ethereum scaling.