Based resources

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Builders/relays/gateways weighing PBS market structure.

📖 release

Fabric Released a rich set of community writing & research on based rollups + preconfs. Highlights include based rollups 101, how based rollups fit within broader composability, and 150 aggregated/organized links to research on based rollups & based preconfs.

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Some updates around EIP-7917 from Nethermind, updates on Fabric from Jason, prover incentives from Open Zeppelin, and blob sharing from Spire Labs & Nethermind.

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Lin from Nethermind presents a simple, yet impactful EIP-7917. This not only helps strengthen Ethereum, but impacts commitments that require a lookahead.

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First official Fabric call on the landscape/status of based rollup components/sub-components for based rollups and ended with Nethermind around the Lookahead for Preconfs.

Gattaca released a reference open-source implementation of a Phase 1 based OP stack, in collaboration with LambdaClass

Many founders, including 10 rollup founders, shared their support for based and/or native rollups. Here are the summary from Justin.

Part 1—based and native rollups

Part 2—FABRIC: Fabric to Accelerate Based Rollup Infrastructure and Connectivity

Vitalik Buterin: "our community thrives on open source, open research [...] It's amazing to see all of this interest and willingness to work together on sequencing and interoperability

2025 will focus on consumer-facing experiences, with infrastructure prioritizing fast, cost-effective apps like Unichain and Hyperliquid.

This series explores how Preconfirmation enhances Ethereum UX while preserving decentralization and neutrality.

Based rollups are incredibly based & in this episode mteam from spire Labs is gonna tell us why, how based rollups are better than traditional rollups, why Based Rollups on Ethereum instead of Celestia but before that we into the fact that he’s 17 years old, any lets get to it

Justin Drake of the Ethereum Foundation joins The Gwart Show! We discuss his Beam Chain proposal, covering improvements in block production, staking mechanics, and cryptography. He explains the path toward more efficient validation and the future of Layer 2 scaling solutions.

A high-level overview diagram and thread explaining how based blocks get built.

A high-level overview diagram and thread explaining how based rollups work.

A technical blog post explaining shared blob compression with Blob aggregator architecture examples

LidoConnect 24

Preconfirmations are the talk of the town, but what are they? In this fireside chat, Eugene Pshenichny and Max Resnick unpack the concept of preconfs, their potential benefits, and whether they could shape the future of the Ethereum network.

LidoConnect 24

mteam from Spire Labs explores the concept of "based" rollups and preconfirmations, providing a clear definition and examining their practical applications. The talk delves into the future of based sequencing and based preconfirmations, highlighting their potential to shape the Ethereum ecosystem and beyond.

LidoConnect 24

Conor McMenamin from Nethermind presents a compelling case for why preconfirmations (preconfs) are inevitable in Ethereum’s future. This talk introduces popular preconf designs, explores revenue models, and demonstrates their economic viability, while positing the likely effects of preconfs on Layer 1.

LidoConnect 24

Jonas Bostoen from Bolt (Chainbound) provides a detailed overview of preconfirmations and their role in Ethereum’s future. This talk covers the rationale behind inclusion preconfirmations, the functionality of Bolt, and its implications for node operators. Jonas also discusses recent developments, the Holesky testnet, and what lies ahead for this groundbreaking innovation.

First based preconfs on mainnet! 🕶️

Block 21,180,697 landed the first ever preconfed NFT mint and L1 transfer. Slot durations will matter less and less as transactions increasingly get preconfed for fast UX.

This milestone is the culmination of a collaborative sprint that started at Edge City sequencing week just a few days ago.

As part of Devcon 2024, Puffer Finance, Espresso Systems, and Radius invite you to join us on November 15th for Sequencing Day!

Set in the vibrant city of Bangkok, Sequencing Day boasts an impressive line-up, with some of Web3's most prominent industry leaders as speakers, and panelists.

@mteamisloading explores why the future of Ethereum Rollups is inevitably based. Many people said this was the most impressive technical talk at the Bankless Summit. I don’t know what you were doing when you were 17 but we certainly weren't doing anything like this...

Matthew Edelen from Spire Labs gives a talk on why based sequencing is so important at Sequencing Day 2024, held Nov. 15 in Bangkok during Devcon.

Justin kicked off the call with some updates on the last couple months and discussed the efforts in Chiang Mai and the updates on the ecosystem.

Facet discussed their high-level direction as a sovereign roll-up designed for “bad times,” addressing L2 attacks and shutdown scenarios, including the 30-day window for stage-two roll-ups. Tom outlined Facet’s unique positioning as a based roll-up, distinct from others on L2Beat, and its solutions for resilience, such as based sequencing, DAOs, and enshrined roll-ups. He explained Facet’s mechanics, including its Optimism fork foundation, transaction-level inclusion, native token (FCT), optimistic bridging, and roadmap features like batching and fault proofs.

Tom also addressed arguments against Facet, such as bridge fragmentation and gas token concerns, while clarifying differences from current roll-ups. In the Q&A, topics included bridge security, native asset risks, forced inclusion, FCT dynamics, and mint rates, with Tom emphasizing network effects and Facet’s evolving trust model.

Kevin’s discussion on preconf pricing focused on the practical aspects of pricing rather than ideological considerations, starting with a framework for approaching pricing within Ethereum. He delved into the option pricing methodology, the assumptions and trading strategies informing preconf prices, and the considerations for building a marketplace through ETHgas.

Kevin highlighted the centralized nature of their product, with plans for future decentralization, and outlined goals like reducing fragmentation, increasing access, and supporting neutrality. He discussed challenges in market dynamics, the need for a unified gateway, auction mechanisms for execution and inclusion preconfs, and potential market structures.

Participants raised questions about centralization, sequencing for roll-ups, operational complexities, shared collateral, and execution guarantees, with Kevin addressing nuances and market-driven dynamics while emphasizing the importance of neutrality in building a unified market.

The talk was divided into three parts: the problem of pricing, design goals, and the construction of preconf pricing. Justin began by outlining the challenges of pricing preconfs, including trade-offs for proposers and opportunity costs. He detailed the design goals, such as preventing front-running, ensuring competitive pricing via auctions, and enabling users to capture backruns with optimal latency and strict profitability.

Justin emphasized the importance of gateways functioning as simple, reputation-driven “dumb pipes” with no room for abuse. He also discussed integrating preconf tip pricing with order flow auctions to improve market efficiency. Moving to construction, Justin explained the mechanics of preconf inclusion, where bids meet minimum asks, and how tips compensate for opportunity costs. He highlighted the long-term need for encrypted preconfs and shared insights on incentives, noting relays’ suitability for operating the system.

In Q&A, topics included gateway and pricer dynamics, user experience, gas price sensitivity, and potential volatility impacts on base fees, with Justin emphasizing UX and user education as critical components.

Demo #1 – Gattaca (Kubi and Lorenzo)

The call began with a refresher on inclusion preconfs from ZuBerlin and L2 execution preconfs. Gattaca showcased their preconf RPC/Router built on Helder to facilitate L2 execution preconfs, allowing users to directly request preconfs via the RPC. The router determines the correct elected gateway or proposer based on the lookahead, demonstrated using MetaMask. Kubi explained that the gateway maintains and advances state, enabling rapid preconfs with testing speeds around 20ms, though it currently supports only L1 inclusion, not execution. Lorenzo demonstrated the potential UX, and Kubi confirmed the approach aims to be L2-agnostic, not limited to Taiko. Discussions are ongoing with MetaMask about developing a Snap for improved UX.

Demo #2 – Bolt (Jonas)

Jonas presented Bolt’s progress since ZuBerlin, highlighting advancements in proposer discovery, local fallback block building, blob support, and bundle support. During a demo, he showcased an ETH transfer with L1 inclusion preconf integrated with MetaMask, including a signature request and transaction sent via RPC, supported by log excerpts. Next steps include researching use cases, economic modeling, slashing/freezing, fair exchange, and new commitment types, as well as commit-boost integration, registry implementation, and finalizing constraints-API, with deployment on Holesky targeted by the end of September. Responding to questions, Jonas confirmed that while bundles are included in the same order, Bolt offers only inclusion guarantees, not execution guarantees. He also mentioned exploring a block space claim commitment for reserving block space in advance.

Demo #3 – Switchboard team / Nethermind (Lin and Maciej)

The project, funded and developed in collaboration with Taiko, was presented by Lin, who outlined the design overview. The L1 slot is divided into four 3-second sub-slots, with a preconfirmer preconfirming an L2 block at the end of each sub-slot. Lin explained their use of batch preconfirmations, which addresses pricing via auctions within batches but sacrifices latency speed compared to continuous preconfs. Maciej demonstrated the preconf process with supporting visuals. Next steps include designing the ECSDA-to-BLS mapping, implementing AVS P2P, and addressing future challenges such as the fair exchange problem, improving the election mechanism, and advancing L2 PBS. A discussion followed about batching and the role of searchers between Justin, Lin, and other participants.

Demo #4 - Primev (Murat)

Murat outlined the process from bid to commitment to rewards, supported by a diagram. He noted that the oracle is currently centralized but transitioning to an AVS. The demo showcased the ability to set bid validity timeframes using decay timestamps, addressing the fair exchange problem through optionality. Murat also discussed analysis of bids on Holesky, highlighting erratic behavior observed among bidders.

A set of topics selected from the pool of open questions identified or proposed, will be pre-assigned Navigators based on domain of expertise and interest. The goal is to guide each of the group to work as quickly as possible to either get to a rough spec, surface dependencies and come to a next step or conclusion.

Zuberlin MEV Day

[Debate] Steelman Challenge: We are all building the same damn thing! Part 4

Zuberlin MEV Day

Vitalik talks about the risks of overloading the proposer.

tl;dr: We solve one of the largest problems with based preconf opt-in from proposers: accidental liveness slashing. The mechanism we introduce requires no changes to existing based preconf protocol designs and has been under our noses the whole time. We use preconf chaining to protect individual proposers from being slashed for liveness failures.

Zuberlin MEV Day

[Debate] Steelman Challenge: We are all building the same damn thing! Part 3

An incredibly detailed blog post about Optimizing State Machine Replication (SMR), Universal Synchronous Composability, Ethereum Based Rollups, Preconfirmations, Fast Based Rollups.

Niran introduced Keyspace as a roll-up focused on providing Base and Coinbase Wallet users with a unified experience across ecosystems. He explained Keyspace’s integration with based sequencing and L2s, emphasizing their goal to leverage decentralization and liveness features.

Keyspace uses Wormhole oracles to manage roots across L1 and L2 networks, though alternative solutions are being explored. Niran detailed wallet, bundler, and roll-up integrations, along with the roadmap, which includes exploring L3 transitions, optimizations, user fee aggregation, and intent-based recovery mechanisms.

In the Q&A, Niran addressed topics such as based sequencing’s appeal (e.g., leveraging Ethereum validators to minimize liveness risks), the current permissionless proving/sequencing design, and latency considerations for key changes. He noted that upgrades would follow a no-governance model similar to Uniswap. Niran also discussed trade-offs in using oracles, the team’s size (three members), and their quarterly release cycle, aiming to implement based sequencing early next year.

The session concluded with a discussion on mitigating risks in vanilla based sequencing when no L1 proposers are available in the lookahead period.

Justin introduced the importance of collateral in based sequencing, with Matthew, co-founder and CPO of Spire, presenting a solution involving a registration smart contract on mainnet where preconfers can register by providing collateral. This collateral can be shared among registrants, and most complexity lies in off-chain dynamics, with underwriters as key actors. Matthew described how home stakers could participate alongside sophisticated actors and discussed trade-offs and mitigations, including dynamic collateral requirements and forced ejection to enforce slashing.

In the Q&A, participants asked about slashing enforcement, the role of underwriters in turning reputation into ETH, and whether collateral is necessary. Matthew and Justin emphasized the need for collateral and standardization through a registry for alignment across L2s. Reputation’s role in maintaining pristine ETH collateral and censorship resistance was also discussed, with execution tickets highlighted as a way to address trade-offs and potentially increase pooling.

Further questions explored the underwriter’s collateral requirements, delegation mechanisms, and risks like long-term de-pegging. Justin and Matthew debated standardization of slashing mechanisms, weighing trade-offs between having a unified model and decentralization.

George and the LimeChain team, supported by an EF grant, presented their research on decentralized sequencers. George outlined the limitations of centralized sequencers and the principles guiding decentralized design, emphasizing security, UX preservation, economic sustainability, composability, Ethereum-based liveness, and censorship resistance through protocol rather than trust. Their analysis favored vanilla based sequencing as the optimal approach, aligning 80% with Justin’s recent discussions.

George detailed their proposed standards for user preconfs, covering timing, rejection reasons, pricing, and transaction fields. Payment mechanisms, including ETH or alternative tokens, were noted as flexible. He introduced Gmev-boost, a fork of MEV-boost, enabling block construction with preconfs and based sequencing, and discussed how builders, proposers, and sequencers would orchestrate block construction and preconf inclusion.

Participants explored topics such as payment methods, latency impacts on signatures, fallback sequencers, and the requirements for running Gmev-boost. George addressed trade-offs and highlighted that while fallback reliance and slashing mechanisms remain challenges, these issues are expected to diminish as the ecosystem matures.

Justin presented on bootstrapping preconfs, focusing on design ideas and coordination games. He addressed the lookahead problem, where no preconfers are available in the lookahead period, proposing a fallback mechanism that delegates preconf rights to a random sequencer if none are present. He explained sequencer-proposer interactions and solutions for preconf overloads, likening the system to a preconf pool. Justin also discussed stake freezing, where collateral is frozen rather than slashed during the bootstrapping phase to mitigate risks, though participants debated the potential impact on essential sequencers. He rejected the idea of higher issuance for preconf proposers.

In the coordination games section, Justin proposed using Taiko as a shelling point and emphasized credible neutrality through sequencer elections and open markets for commitments. He noted that MEV’s absence in the near term might naturally aid preconf market development. Justin shared a timeline, stating this year marks the transition from concept to initial implementation, and addressed Q&A topics, including adoption, infrastructure needs for collateral, and gas efficiency.

Sacha, representing the Lido community, highlighted Lido’s commitment to Ethereum-aligned validator services and its focus on advancing based sequencing without dominating early adoption. He emphasized credible neutrality and collaboration, shared Lido’s guiding principles, and expressed optimism about validator services and preconfs. Sacha fielded questions on transaction flows and risks, emphasizing flexibility while favoring the fastest path forward.

tl;dr: We introduce a design for a credibly neutral preconfirmations registry that solves the collateral problem for solo-stakers who want to earn additional yield from preconfs, while simultaneously improving capital efficiency for large operators who would like to opt-in to preconfirmations.

Dear Taiko Community,

We’re excited to announce that after two years of hard work, the Taiko protocol has been deployed on Ethereum mainnet. 🥳

Taiko’s mainnet launch is a major milestone for all of us — the core contributors, the community, the wider Ethereum community, and the Ethereum protocol itself. Without everyone’s energy, time, and enthusiasm, we wouldn’t be where we are today. Thank you everyone! 💓

Now let’s look at the launch details and what you can do now on the Taiko network.

Discussion about Aztec and privacy-focused L2s going Based.

Cooper opened the presentation with a lighthearted meme and disclaimers, emphasizing the goal of engaging the community to inform decisions about Aztec and roll-ups. He noted Aztec is not currently based but is exploring the possibility. He outlined benefits of based sequencers, such as faster block times, reduced engineering work, synchronous composability, and Ethereum alignment, while also presenting counterarguments, including reliance on Ethereum’s roadmap, reduced roll-up sovereignty, undefined economics, potential L1 censorship, and cost increases from L1 congestion.

Cooper discussed Aztec’s roadmap, highlighting the importance of decentralizing the sequencer and how based roll-ups could enhance performance. He contrasted based sequencing with other options, summarized trade-offs between based and sovereign roll-up designs, and shared Aztec’s research on sequencing. He also explored potential designs for based sequencers, including a simple model and an economic-based approach, addressing blob censorship through inclusion lists and an encrypted blob registry.

The discussion included philosophical approaches to L1 transaction censorship and a poll on Aztec adopting a based roll-up model. Cooper addressed governance and sovereignty concerns raised by participants, noting trade-offs with synchronous composability and data availability. Justin and Cooper expanded on governance implications, data availability dynamics, and the potential of encrypted blob registries.

Participants discussed technical trade-offs, censorship resistance, and the impact of restaking on governance minimization. The poll results showed 89% support for Aztec becoming a based roll-up, with 10% against. The call concluded with a humorous note about one contrarian vote.

Sequencing ensures the correct ordering of transactions to maintain consistent blockchain states. On Ethereum L1, proposers manage sequencing with decentralization at a macro level but centralization within each 12-second slot, while L2s often centralize both ordering and finalization. Decentralizing sequencers is debated for its impact on censorship resistance, monopoly risks, and rollup economics.

Approaches like Based Rollups leverage L1 proposers, ensuring 100% Ethereum security and liveness, synchronous composability, and credible neutrality, but share MEV with L1 validators. Shared Sequencing offers similar benefits without relying on L1 but requires high node availability. Escape hatches add resilience but don’t fully address economic concerns. Hybrid models may adapt sequencing to dynamic environments, balancing decentralization and efficiency.

TLDR: Espresso has proposed creating a marketplace for shared sequencing through which layer-2 chains sell blockspace to shared proposers, including the proposer for the Ethereum mainnet EVM itself, who create surplus value by satisfying user intents across multiple chains.

Brendan from Polygon introduced the Aggregation (Agg) Layer, designed to address fragmentation between zk-rollups lacking shared sequencers, reducing cross-chain latency. Currently, moving assets across zk-rollups like Polygon zkEVM and zkSync involves multiple steps and a latency penalty exceeding 25 minutes.

The AggLayer, combined with a coordination mechanism like shared sequencing, provides neutral public infrastructure for asynchronous and synchronous cross-chain interoperability. It aggregates zk-rollup proofs, validates cross-L2 transactions, enforces bridge invariants to prevent over-withdrawals, and ensures aggregated validity proofs to L1. It enables asset fungibility across L1 and L2 without relying on wrapped tokens or routing through L1.

To mitigate risks from unsound provers, the AggLayer tracks aggregate token balances and prevents withdrawals exceeding locked funds through “Interchain Accounting Proofs.” This mirrors L1 guarantees, ensuring safety and efficiency in cross-rollup interactions.

Alex from MatterLabs expressed concerns about centralization risks with sequencers, including based sequencing, emphasizing the need for a trustless framework and reduced centralization as top priorities before driving adoption. He highlighted two key focus areas for roll-ups: establishing endgame goals for sequencing and ensuring connectivity for seamless roll-up exits and interoperability. Participants discussed the importance of designing shared sequencing systems that allow roll-ups to customize features while addressing centralization and censorship resistance challenges. Justin summarized that demand for synchronous composability will drive shared sequencing, stressing the need for low barriers to entry.

Kalman from MatterLabs presented on achieving universal synchronous composability (USC) and L2 interoperability standards, focusing on shared bridges with asset verifiers and mass deposit sharing. Trade-offs and next steps for these solutions were discussed, with a Telegram group shared for further collaboration. Updates included Espresso’s marketplace for sequencing, Ultrasound Relay’s pre-confirmation role, and Limechain’s research on “Based Ticketing Roll-ups.”

In the Q&A, synchronous composability was explored, with Justin clarifying its broad applicability beyond asset transfers and highlighting the asset verifier solution’s centrality to these efforts.

A useful glossary of preconfirmation related terms and requirements.

An FAQ covering Rollups, Preconfirmations, Based Rollups, and Based Preconfirmations

Ethereum’s rollup-centric roadmap has led to fragmentation in composability as L2s operate as isolated silos, eroding network effects. Shared sequencing and real-time settlement can reintroduce universal synchronous composability (USC), enabling seamless interactions between contracts across L2s and reviving Ethereum’s ecosystem efficiency.

Shared sequencing allows Ethereum L1 proposers to serve as L2 sequencers, combining Ethereum’s security and neutrality with streamlined composability and reduced costs. While USC enhances liquidity, gas efficiency, and decentralized app development, challenges include MEV distribution and engineering complexity for censorship resistance. A shared, decentralized sequencer aligns incentives across L2s, fosters competition on innovation rather than sequencing, and leverages Ethereum’s $70B economic security.

By introducing preconfirmations and adapting existing systems like PBS, Ethereum can transform into a sequencing-centric ecosystem without additional trust assumptions, creating massive opportunities for scalability and network growth.

In this note we describe a version of Ethereum shared sequencing for "based rollups" that retains the benefits of vanilla based sequencing (liveness, censorship resistance, L1 security and composability etc) while offering rollups stronger finality and a share of sequencing revenue. These are two separate ideas, one that leverages a separate BFT finality gadget (in which L1 validators can optionally participate), and one that uses a proposer selection mechanism similar to execution tickets.

I’d like to make two claims:

No single chain, whether L1 or L2, can support the throughput required to reach Internet scale.
Scaling blockchains means scaling access to liquidity and shared state. Adding blockspace via multiple chains doesn’t work if it fragments liquidity.

This represents a challenge to both the modular and the monolithic views of blockchain scalability. (1) is a challenge to the monolithic view, which holds that a single high-throughput chain is the best way to scale. (2) is a challenge to the modular view, because it means that a multi-chain or multi-rollup ecosystem is not sufficient for scaling in a meaningful sense: increasing access to shared state and liquidity..

tl;dr: Based rollups take advantage of the sophisticated L1 MEV infrastructure to sequence L2 blocks. L2 proposers submit transactions to L1 that they retrieve from L2 users. The design of the system of transaction submission (from users to proposers) is a critical part of the rollup design. This post explores the trade-offs between different ways to submit transactions to the rollup.

tl;dr: In this post, I examine a few problems in existing Preconfirmation proposals. I introduce a new role: “The Preconfirmation Gateway” to completely abstract preconfirmations from users. I also explore a few examples of how the gateway may be able to facilitate coordination between preconfers.

Around The Merge, I started to think about leverage and market dynamics that would evolve in Ethereum’s transaction lifecycle. When speaking with researchers, builders, and MEV tourists, all but one pointed to block builders and validators as key parts to the puzzle—however, one standout highlighted the relay as the “watchtower” with the crucial role of coordination. Initially, I laughed, thinking that a relay could never make money… Fast forward and it became clear that both views were correct; relays are watchtowers and weren’t successfully monetizing. But, as we continued research around block builders and blockspace, we realized we could be missing something subtle about the power the relay wields.

Preconfirmations, or preconfs, which we define in the next section, aim to reduce execution risk related to blockspace contention, transaction ordering, and differences in execution compared to other domains ranging from different blockchains to CeFi. Preconfs can be played as a fast game to serve as a proxy for cross-domain price equilibriums, to hedge against gas volatility as well as rights or locks towards a given transaction, state, block, or slot.

While preconfs can also be used to power consumer experiences, the economically dominant use cases are likely to be trading related, arbitraging the price differences created by different execution profiles across domains. We focus on transaction preconfirmations in this document, which by nature are in near real-time.

Exploring every upgrade Chains and Wallets can make so the L2 ecosystem feels like one chain.

The presentations covered key topics in L1/L2 interoperability, preconfirmation models, censorship concerns, and shared sequencer design.

Ellie from Espresso highlighted the dynamics of conditional finality and the trade-offs between fast finality and strong guarantees in based sequencers.

Cooper from Aztec discussed censorship challenges and the design considerations for shared sequencers to address these concerns.

Jonas from Chainbound explained delegation roles in preconfirmation models and the potential role of relays and node operators.

Ben from Espresso focused on aligning roll-up and sequencer incentives, proposing systems to share sequencing revenues.

Ye from Scroll addressed performance challenges for shared sequencers, emphasizing global sequencing mechanisms.

Alex Watts from Fastlane detailed potential market manipulation attacks on preconfirmations and proposed mitigation strategies.

Each presentation emphasized the complexities and opportunities in achieving secure, efficient, and interoperable roll-up ecosystems.

Justin presented the motivations and construction of based sequencing and preconfirms, focusing on creating a unified Ethereum experience where roll-ups operate cohesively with minimal friction. He proposed leveraging Ethereum’s beacon chain look-ahead period for proposers to opt into based sequencing by posting collateral. Users would request preconfirms from these proposers, who promise future inclusion and execution, with slashing penalties for failure. Justin detailed communication flows via MEV Boost and suggested relays as potential facilitators for auctioning and pricing preconfirms, ensuring liveliness.

During the Q&A, attendees discussed challenges like suboptimal block value, complexities with multiple preconfers, and pricing mechanisms. Questions addressed timing games, user preconfer selection, and trust concerns, with Justin emphasizing the need for flexibility and exploration in preconfirm execution designs. The session highlighted both opportunities and unresolved challenges in achieving a decentralized sequencing framework.

Justin introduced the group by emphasizing that the greatest challenge in based sequencing and preconfirmations is social coordination rather than technical implementation. Attendees, including MEV infrastructure teams, rollups, investors, and researchers, shared their experiences and interests in these concepts. MEV teams highlighted ongoing experimentation, with some presenting testnet MVPs for preconfirmations. Rollup teams noted active research, grant programs, and the potential of preconfirms and based sequencing to address rollup fragmentation. Investors expressed enthusiasm and shared insights on Ethereum implications, while researchers tied these ideas to blockspace futures and emphasized the need for education to build social consensus.

The group discussed resources for exploration and implementation, such as events (e.g., ZuBerlin), grants from Taiko, the Ethereum Foundation, and Flashbots, as well as hiring needs across projects like Espresso, Flashbots, and Scroll. Coordination strategies included involving additional stakeholders, developing demos, aligning on standards, and organizing an event focused on these concepts to foster collaboration and drive adoption.

tl;dr: Based rollups don’t need a complicated auctioning system to reward proposers if they are willing to sacrifice L2 MEV rewards

This document outlines a protocol which allows for based preconfirmations, while ensuring the based rollup captures much of the value generated from block building.

The execution ticket mechanism introduces a novel approach to block proposal rights, creating an in-protocol market for buying and selling tickets. These tickets grant the owner the right to propose future execution blocks, using a dynamic pricing mechanism to regulate ticket supply. Tickets are single-use, valid only for a specific randomly assigned slot, and integrate into a dual-lottery system: one for selecting the beacon block proposer and attesters (current Proof-of-Stake process) and another for determining the execution block proposer. Execution tickets separate beacon blocks, which include an “inclusion list” of transactions, from execution blocks, which finalize transactions and update state. Proposers of execution blocks post collateral to ensure proper behavior, with penalties for violations.

This framework contrasts with the current perpetual ticket model for validators, where block proposal rights are inherent to validators. Instead, execution tickets must be explicitly purchased, creating a more transparent and flexible market. For example, hypothetical calculations suggest the “price of being a proposer” aligns with opportunity costs for validators today, providing a baseline for ticket pricing.

Execution tickets complement existing concepts like PBS (Proposer-Builder Separation) but remain distinct, establishing a primary market for future block space while leaving secondary markets like MEV-boost intact. By decoupling MEV rewards from beacon block production, execution tickets aim to mitigate centralizing forces, preserving the decentralized integrity of the validator set.

Proposer-Promised Preconfirmations (PP) streamline transaction guarantees by involving only individual validators, known as preconfers, rather than requiring consensus from the entire validator set. Preconfers opt into a protocol where they can be slashed for failing to honor their preconfirmation promises, offering customizable guarantees like strict execution against a specific state root or simpler inclusion promises.

Users interact with preconfers through a three-step process: sending an off-chain request with bundled transactions and fees, receiving a slashable promise if approved, and verifying the promise to ensure conditions are met. This system reduces centralization pressures, supports diverse rollup needs, and ensures fair exchange mechanisms by bundling fees with transactions to prevent misuse.

The Espresso Sequencer aims to decentralize rollups while preserving the UX advantages of centralized sequencers and improving interoperability between rollups to address liquidity fragmentation across L2s. With the recent Cortado testnet launch, it now supports two rollups from different stacks (OP Stack and Polygon zkEVM) on the same decentralized sequencer.

This post introduces the derivation pipeline, which connects a rollup’s execution layer to the sequencer, enabling easy deployment and customization. By modifying the derivation pipeline, rollups can add features like cross-chain atomic transaction bundles, leveraging the Espresso Sequencer’s atomic inclusion capabilities without altering their execution layer.

Current shared sequencer solutions like Espresso use a pipelined BFT algorithm(HotShot) for achieving consensus among the several sequencer nodes.

There are significant challenges in MEV (Maximal Extractable Value) extraction in blockchain systems using pipelined BFT algorithms to achieve consensus. This detailed analysis explores the nuances of these challenges and proposes innovative solutions to ensure liveness of the network.

Ethereum’s rollup-centric roadmap sacrifices the atomic composability of its shared L1 state machine for scalability, but rollups face limits in supporting applications and lack native interoperability. This has led to the rise of middleware blockchains for shared sequencing, enabling liquidity sharing and partial composability across rollups. However, this approach introduces trade-offs, such as losing Ethereum’s L1 liveness guarantees and credible neutrality due to reliance on alternative consensus mechanisms.

Based rollups propose a censorship-resistant future centered on Ethereum’s base layer neutrality and liveness. This inclusive vision allows existing rollups, like Optimism, to adopt the model without disrupting their business models, fostering a more decentralized and composable ecosystem.

These debates largely come down to security. Unfortunately, defining “security” here has been quite elusive. We mostly use the term casually where most people know roughly what we’re talking about, but not quite. We’ll break down security in detail here across different architectures.

As Ethereum’s growth has turned scalability concerns into practical challenges, rollups have emerged as a key solution, moving transaction execution off-chain while proving correctness to the L1. Rollups come in two forms: optimistic rollups, which use fraud proofs, and zk-rollups, which rely on validity proofs. Their popularity has led to a diverse ecosystem of rollups, supported by Ethereum’s rollup-centric roadmap and rollup-as-a-service startups.

Despite their advantages in scaling, rollups face two major issues: reliance on centralized sequencers creates risks of monopoly pricing and censorship, and the proliferation of rollups fragments liquidity and composability within the Ethereum ecosystem. While decentralizing rollup sequencers can address censorship and pricing concerns, it does not solve fragmentation. The Espresso Sequencer, a decentralized and shared solution across rollups, tackles both issues, enhancing scalability and interoperability by defragmenting the L2 ecosystem.

Layer 2 rollups are delivering on their promise to scale Ethereum and make it useful for a wider range of users and applications, but currently rely on centralized sequencers.

Espresso Systems is developing the Espresso Sequencer to support rollups in decentralizing, without compromising on scale.

The Espresso Sequencer is designed to offer rollups a means of achieving credible neutrality, enhanced interoperability, mitigation of negative effects of MEV, and long-term economic incentive alignment with L1 validators.

TLDR: We highlight a special subset of rollups we call “based” or “L1-sequenced”. The sequencing of such rollups—based sequencing—is maximally simple and inherits L1 liveness and decentralisation. Moreover, based rollups are particularly economically aligned with their base L1.

Join Hasu from Flashbots for a talk titled "Decentralizing Sequencers Wait it’s all PBS Always have been".

We will be celebrating and highlighting the economics of MEV⎯ join us for our MEVconomic.wtf summit! By bringing together thought leaders and contributors from various fields of research and development, we will explore the most recent advancements in the sphere. You will gain an understanding of macro patterns in MEV and how distribution processes interact, for example, mechanisms of the L1 and L2s, data availability layer, restaking and liquid staking protocols.

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