A based rollup, also called an L1-sequenced rollup, is a Layer 2 system and type of rollup whose transaction ordering is driven by its base layer. In the Ethereum design described by Justin Drake, an Ethereum proposer can work with searchers and builders to include a rollup block in an Ethereum block. “Based” describes who drives sequencing; it does not mean every part of the rollup runs on Ethereum.
How Based Sequencing Works
Many rollups use a separate sequencer or sequencer committee to collect transactions, decide their order, and publish batches or commitments to a base chain. A based rollup moves the ordering role to the base chain’s block-production process. On Ethereum, a proposer may include the next rollup block in an Ethereum block, often with help from builders and searchers.
The exact transaction path depends on the protocol. Users do not necessarily send every rollup transaction directly to Ethereum’s public mempool. A rollup may use its own transaction-submission or builder infrastructure, while the ordering that determines its canonical block is based on the L1. Rollup nodes still execute transactions under the rollup’s rules and derive the resulting state.
Sequencing is only one part of the system. A based rollup still needs an execution environment, a method to prove or challenge state transitions, a way to publish or provide data availability, settlement contracts, bridges, upgrade rules, and a path for users to submit transactions. These choices determine important security and usability properties.
What Based Sequencing Can Change
Using the base chain’s proposer and builder market can reduce a rollup’s reliance on a separate privileged sequencer. The original proposal argues that based sequencing can inherit aspects of the base layer’s liveness and decentralization assumptions and align some transaction-ordering incentives with the base layer.
Those are properties of the sequencing design, not a blanket security guarantee for the entire rollup. A based rollup does not automatically inherit Ethereum’s security for its execution code, proofs, bridge, governance, or upgrade process. Users should check how a specific protocol handles each layer of its system instead of treating the label as a security rating.
Tradeoffs and Preconfirmations
A rollup with its own sequencer can offer quick soft confirmations and more control over ordering services. A based design depends on coordination with the base chain, so confirmation timing, transaction fees, and available ordering policies depend on the L1 and the rollup’s implementation. It can also change where ordering-related value flows; the outcome depends on the protocol’s fee, builder, and proposer rules.
Preconfirmations are a separate way to give users an earlier commitment that a transaction is expected to be included. They can be layered onto a based design, but their speed and reliability depend on the actors, commitments, and failure rules used. A preconfirmation is not the same thing as inclusion in a finalized L1 block.
Based Rollups, Native Rollups, and Shared Sequencing
“Based” and “native” describe different design choices. Based sequencing describes how rollup transactions are ordered. EIP-8079 is a draft proposal for native rollups that would expose Ethereum’s state-transition function through a precompile; its design discussion treats based sequencing as one possible sequencing choice. The proposal is still a draft, and the terms should not be used as synonyms.
Shared sequencing is different again: a separate sequencing network can order transactions for multiple participating rollups. That network has its own consensus and trust assumptions. A rollup can also combine design elements—for example, a protocol may use one system for sequencing and another for data availability or fast confirmations. The labels alone do not tell users how the full system is secured.
Examples and Current Project Claims
Taiko describes its Alethia network as an Ethereum-equivalent, type-1 based rollup in its current documentation. That is a project-specific description, not evidence that all based rollups use the same proof system or architecture. The Puffer UniFi Litepaper is another project document about this design space; it should be read as a proposal for that project rather than a universal specification.
When evaluating any implementation, check its current technical documentation and contracts. Confirm which network orders blocks, where transaction data is available, how state transitions are verified, whether users can force or otherwise recover transaction inclusion, and who can change the system.
History
- March 2023: Justin Drake introduced the “based” or “L1-sequenced” rollup framing in an Ethereum Research post.
- November 2025: EIP-8079, a draft proposal for native rollups, described based sequencing as one possible way to order transactions in that design.
- January 2026: Vitalik Buterin published a research proposal exploring how sequenced blocks and based blocks might be combined with limits and additional assumptions.
Common Misconceptions
- “A based rollup executes entirely on Ethereum.” No. The term refers to sequencing. Rollup execution and other system components can remain separate.
- “Based sequencing automatically makes the whole rollup as secure as Ethereum.” No. Proofs, data availability, bridges, upgrades, and governance still need their own review.
- “Based and native rollups are the same thing.” No. Based describes transaction ordering; native rollup proposals describe other ways to reuse or integrate base-layer execution and verification.
Criticisms and Open Questions
Based sequencing can limit a rollup’s control over transaction ordering and may make fast confirmations harder to provide without extra mechanisms. Reliance on L1 inclusion can also affect latency and fees. Preconfirmations may improve the user experience, but they add design complexity and assumptions that should be assessed separately. The tradeoffs vary by implementation, so there is no single performance or security profile shared by every based rollup.
Social Media Sentiment
In one July 2026 r/ethereum discussion about a proposed Gnosis and Ethereum Economic Zone plan, a commenter asked whether the plan involved a based rollup. Other replies said the proposal had not described based sequencing and referred to a centralized sequencer. This small thread shows how rollup labels can be confused in discussion; it is an anecdotal sample, not a measure of wider opinion.
Last updated: 2026-10
Related Terms
See Also
Sources
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Justin Drake. (March 10, 2023). “Based rollups—superpowers from L1 sequencing.” Ethereum Research.
Summary: Defines based sequencing and outlines its proposed liveness, decentralization, economic-alignment benefits, and tradeoffs.
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Vitalik Buterin. (January 16, 2026). “Combining preconfirmations with based rollups for synchronous composability.” Ethereum Research.
Summary: Explores a design combining sequenced and based blocks, including the conditions and limitations that the proposal would require.
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Luca Donno and Justin Drake. (November 13, 2025). “EIP-8079: Native rollups.” Ethereum Improvement Proposals, draft.
Summary: Proposes exposing Ethereum’s state-transition function for rollups and discusses based sequencing as one possible ordering mode.
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Taiko. “Taiko Documentation.” Official documentation.
Summary: Describes Taiko’s Alethia network as an Ethereum-equivalent, type-1 based rollup; used only for this project-specific example.
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Astria. “Introduction to the Astria Sequencing Layer.” Official documentation.
Summary: Describes a separate sequencing layer intended to be shared among multiple rollups, illustrating how shared sequencing differs from L1-based sequencing.
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Ethereum.org. “Scaling Ethereum.”
Summary: Provides broader context on Ethereum scaling and rollup architecture.
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r/ethereum. (July 23, 2026). “Daily General Discussion.” Reddit.
Summary: One thread contains a question about whether a Gnosis-related proposal was a based rollup and replies distinguishing the proposal from based sequencing; used as a limited sentiment example.