Article reprinted from: ChainFeeds
Original title: (Preconfirmation (feat. Taiko): Make Ethereum Fast for the First Time!)
Written by: Ingeun Kim : : FP
Key Overview
Taiko is a Layer 2 network based on Based Rollup, aiming to achieve full interoperability with Ethereum while promoting the decentralization of the sequencer. In order to solve the delay problem of final confirmation of transactions in the rollup mechanism, Taiko introduced the concept of "Preconfirmation". By ensuring the inclusion and sequence of transactions to users in advance, pre-confirmation effectively alleviates the inefficiency of the transaction confirmation process in the rollup mechanism, thereby significantly improving user experience.
In the Based Preconfirmation model, L1 validators provide users with guarantees of transaction results. Preconfirmers need to pledge margin and comply with the slashing mechanism to ensure the reliability of the system. L2 projects such as Taiko have established reliable transaction finality by introducing a preconfirmation mechanism, creating a more convenient operating environment for services such as DeFi that require real-time confirmation.
Currently, multiple projects have participated in the construction of the pre-confirmation ecosystem. This technological advancement is expected to improve the efficiency of the Ethereum L2 ecosystem, strengthen interoperability with Ethereum, and promote further expansion of the entire ecosystem.
Taiko is steadily moving towards its ultimate goal of being an Ethereum Layer2 solution. To achieve this goal, Taiko prioritizes full interoperability with Ethereum, decentralized sequencers, and developer support. It is worth mentioning that Taiko achieves full interoperability with Ethereum through the Based Rollup architecture, while allowing anyone to participate as a sequencer, thereby achieving the decentralization of the sequencer. However, despite the advantages of the Based Rollup model, its structure itself still has some inherent inefficiencies.
This article will take Taiko as an example to deeply analyze the concept of preconfirmation. As a key component of the Layer2 technology stack, preconfirmation is an important step for Rollup to achieve further development.
Current L2 efficiency issues
As the L2 ecosystem expands, many projects have emerged, bringing many new concepts and technology stacks. However, despite these significant progress, L2 still has some problems that need to be solved in terms of efficiency, especially in key areas that affect user experience, where improving efficiency becomes particularly important.
Inherent limitations of Rollup: Inefficient transaction finality
L2 achieves scalability through Rollup, relying on data availability and transaction processing on L1 platforms such as Ethereum. However, Rollup has an inherent limitation: although transaction ordering and execution can be completed independently, all other processes still need to wait for final confirmation from L1.
This architecture ensures security and data immutability by directly leveraging L1’s block generation and data availability. However, relying on L1 for final confirmation results in slower transaction processing and limited real-time confirmation capabilities, which makes it difficult to meet real-time needs from a user perspective.
In addition, many L2 sequencers and verification nodes are still centralized. This centralization can lead to inefficiencies, such as longer transaction confirmation times and possible operational interruptions, which can affect the transaction processing efficiency of some Rollups and cause confirmation delays.
The concept of pre-confirmation
The concept of pre-confirmation is proposed to solve the problem of low efficiency of final confirmation of transactions in L2 networks. Pre-confirmation allows users to obtain transaction confirmation faster, thereby alleviating the common delays and inefficiencies in the Rollup mechanism.
What problems does pre-qualification aim to solve?
In the Rollup mechanism, the confirmation process after users submit transactions to L2 is always inefficient. Since the centralized L2 sequencer cannot accurately guarantee when transactions will be confirmed on L1, users are often uncertain about the order and results of transactions. For example, users may need to wait a long time for transactions to be included on L1, and if the transaction order is wrong or the results are not ideal, it may cause financial losses from the executed transactions.
In highly volatile market environments, latency and order changes are more prominent because users rely on arbitrage and DeFi services. In these cases, transaction delays or order changes directly lead to lost opportunities. Even users who conduct ordinary transactions may lack confidence in the time and order of transaction confirmation on L1, which in turn raises doubts about the reliability and ease of use of the blockchain.
Therefore, the design goal of pre-confirmation is to make up for these shortcomings, especially to provide a more convenient and reliable transaction experience for those users who are most affected by Rollup inefficiencies.
How does pre-validation solve these problems?
Preconfirmation solves these problems by providing users with transaction inclusion, ordering, and execution guarantees. It provides users with "soft confirmations" through a centralized L2 sequencer and issues preconfirmation certificates to ensure that the transaction will eventually be included on L1.
The main advantage of soft confirmation is that it improves the user experience. Users can receive confirmation certificates immediately after submitting transactions, which ensures that transactions are included on L1 in the expected order, reducing uncertainty, especially in transactions that require quick response, such as arbitrage. In addition, pre-confirmation also enhances users' trust in the L2 system. As users gain confidence in the safe processing of transactions, the overall usage of the L2 ecosystem will also increase. As a result, pre-confirmation plays a key role in improving the efficiency and convenience of Rollup processing.
Is pre-confirmation the ultimate solution?
While soft confirmations from a centralized sequencer can improve the user experience through expected ordering and results, it relies on trust in the sequencer. Without legal or technical enforcement, users can only rely on the reliability of the sequencer. This reliance brings with it the possibility that transactions may not be included in the correct order, or may not even be included on L1 at all, failing to provide the stability guarantees that users expect.
Interpreting the concept and practice of Based Preconfirmation using Taiko as an example
Taiko puts a lot of effort into preconfirmation-based implementation because this approach aligns well with the core features of Based Rollup. If Based Preconfirmation can successfully introduce Taiko's framework, it will not only significantly reduce the delay in final confirmation of transactions, but also improve user experience. Additionally, this improvement will activate a variety of previously restricted services to run efficiently on the Taiko network.
Before we delve into Based Preconfirmation, it is necessary to review some key features of Taiko in order to more fully understand the applicability and advantages of this approach.
Taiko Case Study
Taiko fully demonstrates the core features of Based Rollup. It not only achieves full interoperability with Ethereum infrastructure, but also strives to fully align with Ethereum's security mechanisms. Taiko adopts the Based Rollup architecture, which means that it does not rely on a centralized sequencer, but relies on Ethereum's validators to act as sequencers, responsible for the ordering of transactions and blocks.
In other words, Taiko’s sequencer is the same type of role as Ethereum’s block proposer. This design gives them special responsibilities and incentives, such as maximizing extractable value (MEV) rewards and other benefits that come with sequencer status. Therefore, when problems occur in Taiko's L2 sequencing process, these sequencers will naturally bear corresponding responsibilities due to their interest in the Ethereum ecosystem. This mechanism significantly differentiates Taiko from other Ethereum L2 projects in terms of operational responsibilities.
In addition, it is worth noting that Taiko's Based Rollup model is designed as a "Based Contestable Rollup (BCR)", a structure designed to encourage healthy competition. Through open and permissionless design, Taiko ensures the decentralization of the system and allows anyone to participate, making the system more fair and transparent.
Pre-confirmation based on Based Rollup
So, what is the pre-confirmation model designed specifically for Based Rollup? The answer is "Based Preconfirmation". This model aims to replace the traditional soft confirmation mechanism with confirmations verified directly on L1.
Based Preconfirmation provides a system where some L1 validators voluntarily participate and provide preconfirmation services. As sequencers, these validators provide users with verifiable predictions of the results of Rollup transactions. This approach provides users with trusted guarantees of transaction inclusion and ordering, and these guarantees are directly based on L1, thereby enhancing the credibility and reliability of the Rollup process.
Justin Drake first proposed the concept of Based Preconfirmation and proposed a specific role called "Preconfirmer", who can provide signature guarantees for users and clarify the order and execution status of transactions. In order to ensure the reliability of the commitment, each preconfirmer needs to pledge a certain amount of margin. If they fail to fulfill their commitment on the order or execution status of transactions, they will face the penalty of the Slashing mechanism, that is, the loss of part or all of the margin.
The slashing mechanism has been widely used in Ethereum PoS staking to effectively curb malicious behavior. This mechanism not only strengthens the sense of responsibility of pre-confirmers, but also establishes a certain trust foundation between users and pre-confirmers.
There are two situations that will cause the pre-confirmer to be punished by Slashing:
Liveness Faults: Liveness Faults occur when a pre-confirmer fails to include a user's pre-confirmed transaction on-chain for any reason. Because liveness faults are not always intentional, their penalties are relatively mild. Such faults may result from network issues or outages in the L1 or L2 blockchain, preventing transactions from being correctly included on-chain. To protect honest pre-confirmers from undue penalties, the penalty amount for liveness faults is usually negotiated between the user and the pre-confirmer.
Safety Faults: If a preconfirmed transaction is included on-chain, but the result is inconsistent with the user's original request, a safety fault occurs. This inconsistency is entirely the responsibility of the preconfirmer, so the penalties for safety faults are usually more severe. The preconfirmer's security deposit will be forfeited in full, regardless of whether the problem was intentional or not.
To become a preconfirmation based on the Preconfirmation model, a node (usually an L1 block proposer) must accept the conditions of these slashing mechanisms and pledge the required deposit. Once approved, the preconfirmation can provide services to users and earn income by charging service fees.
This fee model provides significant convenience to users, allowing them to bypass the delays inherent in the final confirmation of Rollup transactions. For example, after a user submits a pre-confirmed transaction through their personal wallet, they can immediately obtain a confirmation certificate from the pre-confirmor.
Preconfirmers who participate in Based Preconfirmation can not only earn additional income by charging fees, but also help optimize the Rollup transaction confirmation process. This model not only improves the user experience, but also provides a reliable and efficient transaction final confirmation solution for the entire L2 ecosystem, further enhancing its attractiveness and practicality.
Why are users willing to pay for pre-confirmation?
This is actually closely related to the core purpose of pre-confirmation. Users are willing to pay for pre-confirmation because it directly solves the inefficiency problem of Rollup in the final confirmation process of transactions and brings significant convenience to users.
For example, when a user submits a pre-confirmed transaction on an L2 blockchain through a personal wallet, a standard transaction may need to wait for final confirmation, while the user requesting pre-confirmation can immediately get assurance from the pre-confirmer that the transaction can be completed without delay. At this point, the user may even see a green check mark in the wallet interface, clearly indicating that the transaction has been successful.
Taking DeFi services as an example, when users exchange tokens on L2 DeFi platforms, pre-confirmation can provide additional protection for related transactions. Usually, the quoted exchange rate or fee of the transaction may be inconsistent with the actual transaction result due to delays. However, through pre-confirmation, users can enjoy a fast and efficient transaction final confirmation process, reduce the difference between expected conditions and actual results, and thus obtain a more reliable service experience.
These application scenarios not only enable developers to provide more precise services, but also bring users a smoother and more convenient user experience. This dynamic further supports the expansion of the L2 ecosystem while also contributing to the growth of the broader L1 ecosystem. In addition, for the sequencer of Based Rollup, the additional income brought by pre-confirmation provides it with a considerable profit model. This design effectively solves some of the traditional weaknesses of Based Rollup, making it an ideal choice for sequencers, combining reliability and attractiveness.
Based Preconfirmation What are the challenges?
Based Preconfirmation is still a hotly debated research area in Rollup-driven Layer2 projects such as Taiko. Although this mechanism provides a clear solution for improving L2 performance and scalability while maintaining decentralization, it still faces some challenges that need to be addressed in practical applications to achieve wider adoption.
First, when a Preconfirmer submits a transaction to a block, users may not be able to obtain an absolute guarantee of transaction inclusion. Although the Preconfirmer provides a guarantee for the transaction through a pledged deposit, this mechanism still cannot completely solve the problem of transaction failure due to external interruptions. Especially when the transaction value is higher than the Preconfirmer's pledge amount, the Preconfirmer may abuse his authority to selectively include or exclude certain transactions, which brings potential risks.
Another significant challenge is the pre-confirmation-based profit model. The main source of income for pre-confirmers is the pre-confirmation fees paid by users. However, if the number of pre-confirmors is insufficient or their participation is not high enough, it may lead to market centralization and monopolistic tendencies. In this case, pre-confirmation fees may be artificially high, increasing the cost for users to conduct fast and efficient transactions, thus posing a threat to the healthy development of the pre-confirmation ecosystem.
It is worth noting that the concept of Based Preconfirmation is relatively new, having been proposed only about a year ago. It will still take some time for it to become a "key tool" to maximize the speed and efficiency of Rollup-driven L2 solutions. However, as Rollup has been firmly established as a core component of Ethereum scalability, further exploring preconfirmation to improve performance marks an important step in the development of L2 technology.
Taiko, in particular, has made significant progress in promoting the implementation of Based Preconfirmation. At the same time, Taiko has collaborated with many partners such as Taiko Gwyneth, Nethermind, Chainbound, Limechain, Primev and Espresso to jointly explore and develop application scenarios of Based Preconfirmation. These collaborations are aimed at promoting the further evolution of the L2 ecosystem, and more details will be discussed in depth in subsequent chapters.
Panoramic view of pre-confirmation ecology: flowchart interpretation and project exploration
In this chapter, we will explore which projects are actively researching and advancing the development of pre-confirmation technology in the Rollup-driven L2 ecosystem. Since the ecosystem is still in its early stages of development, we will use a flowchart to more intuitively display and understand the specific process of pre-confirmation.
Pre-confirmation flow chart
Pre-confirmation is a complex process that requires close collaboration between L1 and L2, involving multiple roles, each with specific responsibilities. In order to facilitate a more intuitive understanding of this process, I have made a flowchart for a brief overview. It should be noted that this flowchart is intended to help explain the overall logic, so it does not strictly distinguish between the different features of Rollup and Based Rollup, but focuses on the general process at the basic level.
Before understanding the specific steps of the flowchart, let's first understand the various roles and functions involved in the pre-confirmation process:
User: An individual user of an L1 or L2 network who is responsible for creating and submitting transactions. If a user wishes to obtain pre-confirmation guarantees, they will send the transaction to the pre-confirmer after writing it.
Preconfirmer: During the preconfirmation process, the preconfirmer is responsible for reviewing the transaction and verifying its validity, and then providing the preconfirmation guarantee to the user. Through preconfirmation, users can quickly obtain the status guarantee of the transaction before the final settlement. If the node is not eligible for preconfirmation, they act as non-preconf actors, mainly processing ordinary transactions rather than preconfirmed transactions, similar to standard verification nodes.
L1 Validator: Responsible for the final verification of transactions and blocks on the L1 network. Once the pre-confirmer submits the transaction data, the L1 validator will verify it and record the final data in the L1 blockchain to ensure the integrity of the transaction and compliance with the consensus rules.
Preconfirmation Challenge Manager: When disputes or issues arise during the preconfirmation process, this role is responsible for investigating the issue and taking appropriate steps to resolve the dispute. This role is critical to maintaining the integrity and accountability of the preconfirmation process.
Now, let's sort out the specific process of pre-confirmation in the order of the flowchart:
The user sends a transaction request to a pre-confirmer among the pre-confirmation participants to start the pre-confirmation process.
The pre-confirmer reviews the transaction and sends a pre-confirmation receipt, promising the user that the transaction will be included in the L1 block, thus providing the user with preliminary final confirmation guarantees.
Pre-confirmers submit transaction data that needs to be included in the L1 block to L1 validators. This data may be a single transaction or a summary of data processed by the L2 sequencer.
L1 validators verify the submitted transaction data or summary data and record it in the L1 block to ensure that it complies with the blockchain consensus rules.
After a period of time, the L1 block containing transaction data or summary data reaches finality, and the transaction is officially confirmed to be completed.
Users can check the finality of transactions through L1 nodes and use the relevant information to raise any potential pre-confirmation disputes or challenges as necessary.
If a transaction is not correctly included on L1 as promised, the pre-confirmer will face penalties from the pre-confirmation challenge manager, such as having their deposit slashed or having their staked assets frozen.
Related Projects to Explore
Below is a detailed analysis of the main projects actively participating in the pre-validation ecosystem and their relevant roles in the process. Although these projects occupy specific roles in the process map, the responsibilities they actually perform may be slightly different. Therefore, this overview is intended to provide a basic understanding and can be used as a general guide. For clarity, the projects in each category are arranged in alphabetical order.
Preconfer Validators
Astria: Astria is committed to replacing centralized sequencers with a decentralized sequencer network and supports multiple Rollups sharing this network. This design provides Rollup with greater censorship resistance, faster block finality, and seamless cross-Rollup interaction. To achieve fast block finality, Astria has introduced pre-confirmation functionality, enabling Rollup to provide fast transaction confirmations and enhanced censorship resistance, significantly improving the user experience.
Bolt by Chainbound: Bolt is a pre-confirmation protocol developed by Chainbound that provides near-instant transaction confirmation services to Ethereum users. It operates based on a trustless participation mechanism and economic collateralization, while being compatible with the existing MEV-Boost PBS pipeline, creating new revenue opportunities for proposers. Bolt's core feature is L1 pre-confirmation, which provides instant finality for basic transactions (such as transfers and authorizations), thereby improving the user experience. By transferring the responsibility for transaction inclusion from centralized block builders to proposers, Bolt enhances the system's censorship resistance. At the same time, the collateral proposer registration mechanism ensures a trustless environment that flexibly supports various types of smart contracts.
Espresso System: Espresso System is a protocol dedicated to enhancing the interoperability of blockchain ecosystems. It uses the HotShot Byzantine Fault Tolerant (BFT) consensus protocol to achieve transaction order and fast data finality across multiple chains. Espresso System includes Espresso Network and Espresso Marketplace, which work together to provide fast transaction finality and efficient interoperability, with the goal of improving the scalability and security of the blockchain ecosystem.
Ethgas: Ethgas is a market for trading block space. Transaction matching is managed by a centralized system, and on-chain processes are executed through smart contracts. Ethgas provides two main functions: inclusion pre-confirmation (ensuring that a transaction is included within a specified Gas limit) and execution pre-confirmation (ensuring that a transaction reaches a specific state or outcome). Ethgas focuses on protecting transaction privacy in block space transactions and is known for its operational goals of neutrality.
Luban: Luban focuses on developing a decentralized ordering layer to connect transaction data between the Ethereum network and Rollup. The ordering layer is designed as a decentralized system that separates proposal and execution roles. Luban’s pre-confirmation feature significantly improves transaction reliability by ensuring a transaction’s executability before being included on the Ethereum network, while helping to optimize key factors such as transaction fees, gas price, and MEV.
Primev: Primev is developing a proposer network integrated with MEV, combining pre-confirmation with MEV functions to build an efficient and reliable peer-to-peer network. This network records the commitment to the execution of Ethereum transactions and incentivizes proposers through a reward or penalty mechanism. Primev allows MEV participants to set specific execution conditions for their transactions, and block builders and validators can commit to meeting these conditions to ensure the pre-confirmation of transactions. Based on EIP-4337, Primev supports flexible pre-confirmation and gas fee options, which not only improves transaction processing efficiency, but also further optimizes the user experience.
Puffer Unifi: Puffer Unifi's Actively Validated Services (AVS) is built on EigenLayer and focuses on solving pre-confirmation challenges in the Ethereum ecosystem, especially in the architecture of Based Rollup. Puffer Unifi AVS leverages EigenLayer's re-staking function to support the pre-confirmation participation mechanism, aiming to improve the efficiency of transaction final confirmation. As Based Rollup develops, the demand for reliable pre-confirmation providers continues to grow, and Puffer Unifi AVS aims to meet this demand. Its ultimate vision is to achieve efficient pre-confirmation without changing the core protocol, thereby promoting sustainable growth of the Ethereum ecosystem.
Skate: Skate’s pre-confirmed AVS relies on re-pledged assets on EigenLayer to provide economic security for all cross-chain operations. This AVS verifies the bundled data and information required for cross-chain transactions, which are then signed by Skate’s relayer and ready for execution. Through this process, Skate AVS achieves pre-confirmation of data, significantly improving the reliability and efficiency of cross-chain transactions.
Spire: Spire's Based Stack is an Ethereum-based Rollup framework designed to support developers in building App Chains. The framework allows App Chains to interact directly with Ethereum and customize their sequencing methods, supporting functions such as cross-chain exchange, while optimizing user experience through pre-confirmation. Based Stack supports multiple execution environments, guarantees sequencing revenue for App Chains, and maintains compatibility with traditional shared sequencers. As an open source project, Based Stack provides developers with the complete tools and resources needed to build and manage App Chains, thereby promoting App Chain development and interoperability of the Ethereum ecosystem.
Taiko Gwyneth: Taiko Gwyneth is a Rollup design being developed by Taiko, which is classified as a based Rollup architecture. Its goal is to achieve full interoperability with Ethereum while managing transaction sequencing directly on Ethereum. This design takes full advantage of the security and decentralization of Ethereum while providing high throughput and fast final confirmation. Currently, Taiko is running a proposer mechanism to assist in block creation and exploring a pre-confirmation mechanism to promote profitable block production within the community. The mechanism is designed to optimize block time scheduling and data publishing efficiency. To achieve these goals, Taiko is working closely with projects such as Nethermind and Gattaca.
L1 Validator
Chorus One: Chorus One is a project that provides verification services and infrastructure for blockchain networks, focusing on staking services in multiple protocols to enhance the stability and security of the network. As an L1 validator, Chorus One's responsibility is to verify transactions and generate blocks, thereby improving the reliability and efficiency of the entire network. Recently, Chorus One has shown great interest in pre-confirmation technology and even held a related special event during Devcon 2024.
Research
Nethermind: Nethermind is a project dedicated to developing Ethereum clients and tools, with the core goal of improving the performance and stability of the blockchain network. By introducing advanced optimization techniques, Nethermind actively promotes the improvement of Ethereum network transaction throughput. Nethermind has been conducting in-depth research on pre-confirmation technology and has submitted a proposal to Taiko's funding program to accelerate the deployment of pre-confirmation functions on the Taiko mainnet. This proposal is based on Nethermind's RFP-001 project and will be implemented in two phases: the first phase will test the pre-confirmation function among a limited number of authorized participants; the second phase plans to gradually expand the scope of application of pre-confirmation.
Looking ahead
Taiko and many other Rollup-based Layer2 projects, whether or not they use the Rollup-based architecture, are working to optimize the inefficient transaction final confirmation process in traditional Rollup. By introducing the concept of preconfirmation, these projects are building a transaction confirmation system that enables users to confirm transactions more quickly and reliably. In this way, these projects continue to explore how to improve user experience and build user trust.
Taiko makes full use of its positioning as a Layer 2 project of Based Rollup and actively promotes the implementation of the Based Preconfirmation mechanism to achieve full interoperability and decentralization with Ethereum. Taiko significantly improves the user experience by providing users with fast and reliable guarantees of final confirmation of transactions, significantly improving transaction processing speed and reliability.
However, several industry experts, including Ed Felten of Arbitrum, pointed out that there is still a lack of mature middleware that can fully support pre-confirmation. This shows that the maturity of pre-confirmation technology and the profit model of pre-confirmers are still facing challenges, and these problems need to be further resolved.
As described in this article, more and more projects and participants are actively entering the pre-confirmation space, each bringing unique and innovative solutions to improve the performance and efficiency of Ethereum Layer2. This trend also fits the general law that system concepts are continuously optimized after initial implementation. I believe that this stage marks an important node in the evolution of L2 systems and is also an exciting and positive development in the current L2 ecosystem.
Improving user convenience through pre-confirmation may not only have a profound impact on areas such as DeFi and games that focus on speed and efficiency, but may also reconnect Ethereum with previously fragmented parts of the ecosystem by improving the performance of Ethereum Layer2. This performance improvement may enable more Type-1 Ethereum Layer2 projects to achieve deep integration with Ethereum, thereby unleashing potential that was previously difficult to obtain due to speed limitations. These developments are bound to have a profound impact on the entire Ethereum ecosystem.
Pre-confirmation is still a challenging and bumpy road. However, pioneers like Taiko are rising to the challenge and focusing on providing more convenience for users. Innovation is never easy, but as a supporter of Ethereum and its Layer2 ecosystem, I sincerely respect and encourage their efforts.
