Developed by Offchain Labs, Timeboost redefines transaction ordering for Arbitrum chains and aims to address some of the challenges with First Come, First Serve (FCFS) ordering, such as spam arising from latency racing and the capture of Maximum Extractable Value (MEV) entirely by searchers. Timeboost allows interested users to participate in an off-chain auction for the right to get their transaction sequenced faster in a block.  

Ultimately, the mechanism enhances block building with speed, predictability, and efficiency, unlocking a new era for L2s. More details on Timeboost can be found in Arbitrum docs and Offchain Labs’ medium page. 

What makes this launch particularly exciting is that Arbitrum will be the first to bring this type of technology into reality. By embracing new technologies before they become the industry standard, Arbitrum shows that it is willing to test, iterate, and implement mechanisms that push traditional L2 boundaries. 

Among the first teams to adopt Timeboost is Gattaca, the research-driven team behind Titan, a leading Ethereum block builder. Titan has played a critical role in shaping the block-building landscape by adhering to three simple values: staying neutral, being transparent, and delivering solid performance.

Fast-forward to today, Gattaca is extending its expertise to Layer 2s by launching its Timeboost implementation, Kairos, now live on Arbitrum One and Arbitrum Nova.

In a conversation with Offchain Labs, Gattaca discusses how it has built trust on Ethereum, why it’s expanding to L2s, and what Timeboost means for the future of MEV infrastructure.

Gattaca Q+A

As operators of one of Ethereum's largest builders, Titan Builder, what has made Gattaca successful in gaining market participants' trust?

Titan Builder is a neutral builder that does not compete against its users. Being neutral helped us bootstrap order flow early on since we don’t favor any specific subset of transactions. We also focus on fair access for all participants, avoiding conflicts of interest.

We’ve built our entire culture around high-performance engineering, having built out a robust, low-latency infrastructure. Reliable execution is essential for searchers on Ethereum, and by focusing on stable and efficient execution, we’ve consistently provided dependable block access. Our emphasis on security underpins this reliability at scale.

In addition to Titan Builder, we’ve also developed Helix, a new open-source relay codebase powering Titan Relay and other initiatives. We’re also a core contributor to Commit Boost and actively support Fabric, contributing engineering and research to advance the Based Rollup ecosystem. These open-source initiatives unlock new possibilities, including faster relay submissions with Optimistic V2 relays and custom proposer commitments for Commit Boost, demonstrating transparency and our dedication to ecosystem growth.

What motivated Gattaca to expand into L2s with Timeboost?

L2s feel like a natural continuation of the sequencing expertise we developed on Ethereum, so plugging our builder engine into something like Timeboost was a clear progression. It builds on the same low-latency infrastructure and core algorithms we already had in place. 

Additionally, the growing L2 ecosystem—particularly Arbitrum—creates an increasing demand for sophisticated infrastructure to handle complex sequencing. Timeboost presents an opportunity to reduce network spam, improve capital efficiency in the L2 space, and align with our broader vision of supporting and enhancing Ethereum at multiple layers.

How will Gattaca’s expertise in L1 block building translate to L2 sequencing with Timeboost? What key differences should market participants understand?

Technically, the big overlap is in how we gather, simulate, and build blocks with minimal overhead. On Ethereum, we often only have the final few milliseconds of block time to finalize a bundle, so we’re used to working under intense speed constraints. Timeboost is similar in the sense that it’s confined to 200ms once the express lane is held.

The major difference is that Timeboost auctions off “express lane” rights for a 60-second window rather than running a first-price auction live for each slot. This means we need to predict the value of a time advantage over a 60-second period to place a fair bid. Pricing this accurately requires a more complex model than a per-block or per-transaction approach.

Timeboost’s MEV Impact

How does Timeboost's ordering policy differ from other approaches?

The main departure is that with Timeboost, the value of the time advantage is effectively paid for upfront by bidding for the express lane. Whoever wins that express lane is more likely to land trades first, so it’s less about raw latency or per-transaction bidding.

The typical dominant strategies are: 

• Purely latency, as Arbitrum was before Timeboost, and
• Priority fee auctions, like Ethereum, where participants bid in real-time for each individual opportunity.

Timeboost evens the playing fields by enabling multiple market participants to engage in the auction, e.g., sub-slot auctions or searchers. Unlike many other MEV approaches, it also maintains Arbitrum's continuous ordering nature, which protects against sandwiching.

What potential use cases does Gattaca expect to see from using Timeboost's express lane auctions?

We anticipate two dominant strategies to emerge with Timeboost:

1. Searchers: Some searcher teams may buy the entire 60-second slot outright, attempting to obtain all MEV according to their strategies during that period. Sniper teams might also pick up multiple consecutive rounds near a predicted token launch. This approach suits firms with deep expertise in pricing short-term opportunities, although the difference here is bidding on total MEV over 60 seconds, rather than just a few seconds.
2. Accessible Markets: Providers (e.g., Gattaca) buy the round-level control and then sub-auction it in real time (e.g., 100ms cycles). This diversifies the types of strategies that can appear because the aggregator spreads the risk (of pre-paying for a 60-second control) across many participants.

What technical advantages does Timeboost's auction design offer compared to other solutions?

• It preserves Arbitrum’s protective properties against sandwiching because the ordering is continuous.
• It allows new entrants to compete since buying a time advantage depends on the searcher’s ability to predict its value rather than on builder performance, similar to Ethereum’s PBS model.
• It can leverage a second-price or similar auction structure, which promotes more efficient price discovery.

What new capabilities or efficiencies do you anticipate Timeboost enabling for your users?

Once someone holds the express lane, either by winning it directly or accessing it via an accessible market, they gain a 200ms advantage on every transaction in that window. This reduces the need for hyper-optimized, microsecond-level setups and opens the door for more sophisticated pathfinding strategies. In addition other benefits include:

• Capital Efficiency: Less need for ultra-fast infra means more investment into modeling and execution.
• Reduced Network Spam: Fewer redundant transactions reduce L1 data costs for the Arbitrum chain.
• Low Impact on General Users: For 99.9% of normal transactions, the experience remains unchanged while benefiting from less congestion.
• Accessible Markets: Lower the barrier for participants who wouldn’t buy a full 60-second slot but still want time advantage access. 

Implementation Plans

What plans does Gattaca have for Timeboost?

With Kairos, we plan to be an active participant in Timeboost auctions, bidding for the 60-second express lane controller on each round. Once we hold the lane, we’ll run a sub-auction every ~100ms, similar to the batch-building logic we use on Ethereum. 

The workflow looks like this:

1. Round Control (60 seconds): We win the round-level auction and secure the express lane rights.
2. Sub-Auctions (~100ms cadence):
   1. During each sub-cycle, we gather all incoming orders from our connected searchers via a bundle API similar to Ethereum.
   2. We simulate each order, calculate the payment, and sort them.
   3. Once we have created an ordering, we send the batch to the Arbitrum sequencer, signed by our express lane key.
3. Beating the 200ms Delay: As long as our total processing plus latency is below 200ms (and any competitor’s latency), our sub-auction bundles land first.

How does Gattaca plan to help market participants use Timeboost?

Our primary focus is on democratizing access to the express lane through Kairos, which includes:

• Risk Management: We take on the up-front bidding risk. Searchers only pay if they succeed in getting their transactions included—similar to our builder model on Ethereum. We also manage the express lane token handling so participants don’t need capital reserves for bidding.
• Market Structuring: We aggregate demand from diverse market participants, letting them focus purely on their own strategies rather than trying to outbid everyone for the full 60 seconds. This helps prevent centralization and reduces the advantage of large capital or speed.
• Technical Integration Support: We’ll keep the same interface (e.g., eth_sendBundle) so searchers can plug into Arbitrum with minimal changes. We also plan to provide documentation, real-time simulation logs, analytics, and guidance for teams transitioning from L1.
• Performance Optimization: Since Timeboost allows more breathing room than microsecond-level races, searchers can focus on optimizing trade logic and pathfinding. We’ll offer tools and analytics to support strategy refinement without needing ultra-low-latency setups.

Next Steps

Is there anything else you think your users should know about Kairos?

Some key takeaways from our accessible market approach:

• We bid directly in the auction on behalf of searchers, handling the challenge of pricing 60 seconds of future MEV.
• When we win round control:
  • We run a first-priced sealed-bid auction every ~100ms, similar to Ethereum.
  • Bundles and transactions are ordered by price, prioritizing optimal value capture.
• The API for integration is the same as Ethereum (eth_sendBundle, eth_sendTransaction).
• Searchers pay only if their bundle is successful.

Overall, we see Timeboost as a way to extend proven L1 builder principles into Arbitrum while preserving the core protections of the chain. By fronting the capital risk and offering a familiar interface, our goal is to make sophisticated L2 MEV strategies accessible and beneficial to a broad set of participants—ultimately driving a more efficient and open market.