Frequently asked questions

Espresso empowers rollups to focus on execution and creating unique user experiences while gaining the speed, security, and interoperability capabilities they need to achieve their full potential.

The Espresso base layer is purpose-built to provide fast, secure finality, low cost data availability, and decentralized sequencing to applications such as rollups and other types of L2s. It consists of a decentralized network of validators that run a custom BFT consensus protocol called HotShot. Rather than having a fixed blocktime, HotShot finalizes blocks as fast as the network allows (e.g. immediately once the leader receives votes from ⅔ of active stake). This enables Espresso to confirm the transaction ordering and data availability of a rollup's block within seconds, offering the fast, secure finality the Ethereum L1 is unable to provide. Espresso does not handle execution.

Espresso’s fast finality enhances a rollup’s security by preventing sequencer equivocation (i.e., sending different versions of the same block to different parties) through a protocol-level restriction that ensures only Espresso-confirmed blocks can be published to the eventual settlement layer. This means other rollups, onchain apps, protocols, etc., can read a rollup’s state from Espresso and safely act upon it without waiting 12+ minutes for L1 settlement. Espresso can also be used on its own as a secure settlement option for rollups.

Rollups today face critical limitations: they’re forced to wait 12+ minutes for Ethereum finality, and lack seamless interoperability with other rollups, protocols, and onchain apps. These challenges prevent rollups from delivering the seamless, crosschain experiences current users want, and all future users will expect.

A purpose-built base layer like Espresso solves these fundamental infrastructure gaps that other L1s weren't built to address.

Espresso supports a growing ecosystem of rollups regardless of tech stack, VM, or even settlement layer. Espresso serves multiple types of users across the blockchain ecosystem:

Rollups and Chains: Various L2s and L3s across different tech stacks integrate with Espresso, including Arbitrum Orbit chains, OP Stack chains, and app-specific rollups. Espresso supports chains regardless of their VM or settlement layer.

App Developers: Developers building crosschain apps can use Espresso’s Caff Nodes to read rollup state derived from Espresso confirmations through standard RPC interfaces, enabling real-time crosschain composability without waiting for L1 settlement.

Interoperability Infrastructure: Bridges, exchanges, relayers, solvers, and other crosschain infrastructure read from Espresso to improve interoperability with integrated chains, acting on BFT consensus-backed confirmations within seconds instead of waiting 12+ minutes for L1 finality.

Espresso confirmations provide BFT consensus-backed transaction finality within seconds rather than the 12+ minutes required when L2s communicate via Ethereum L1. This enables:

• Fast, secure finality: Users receive confirmations backed by BFT consensus, not just centralized sequencers
• Additional security layer: Prevents sequencer equivocation and protects against reorgs by ensuring rollups can only settle blocks that match what Espresso has already confirmed
• Capital-efficient bridging: Intent-based bridges and solvers can rely on Espresso confirmations rather than waiting for slow settlement
• Real-time crosschain composability: Applications, exchanges, and other chains gain immediate insights into the state of all chains across the ecosystem
• Reduced settlement risk: Eliminates cascading reorg risks by providing cryptographically confirmed state commitments that other chains can safely act upon

These benefits transform isolated execution environments into a unified, composable ecosystem where value and data flow seamlessly between chains.

Espresso Mainnet 0.0 is run by a permissioned, geographically distributed network of 100 nodes that participate in Espresso’s consensus protocol (HotShot) and data availability layer (EspressoDA). An upgrade planned for late 2025 will upgrade the network to a permissionless proof-of-stake model.

Fast confirmations enable capital-efficient crosschain trading, better AMM liquidity aggregation, and eventually atomic crosschain transactions. Users can trade assets across chains without lengthy settlement delays, and liquidity providers can operate more efficiently across multiple rollups.

Espresso enables crosschain applications that are impossible with current slow infrastructure, such as crosschain order books, bridgeless crosschain minting, unified gaming experiences spanning multiple rollups, and real-time crosschain arbitrage.

Yes, all chains integrated with Espresso, whether for fast confirmations or decentralized sequencing, by default will benefit from highly efficient, low-cost data availability offered by the Espresso Network. However, chains using Espresso are free to  leverage additional DA solutions, as well, such as Anytrust, EigenDA, Celestia, or Ethereum itself, for added redundancy. We have designed Espresso to be compatible with these choices. For more on how chains use Espresso, go here.

Yes, rollups can use Espresso as a decentralized sequencer. Benefits include stronger censorship resistance and removal of central points of failure compared to centralized sequencers. 

For rollups seeking synchronous composability (i.e., where multiple chains can act as if they are a single blockchain with atomic crosschain transactions) they would need shared sequencing, where the same sequencer orders blocks including transactions from multiple chains simultaneously. While Espresso Research is exploring incentive-compatible shared sequencing mechanisms, including marketplace designs for revenue sharing, Espresso does not currently offer shared sequencing as a product. Development of shared sequencing capabilities would be driven by market demand.

Currently, however, most rollups prefer to maintain their own centralized sequencers for various operational reasons.

While two rollups using Espresso for decentralized sequencing are technically sharing a sequencer, the Espresso Network does not yet support sophisticated crosschain building to fulfill user intents and enable synchronous composability between integrated rollups. This functionality is planned for future releases contingent upon demand. Many chains integrating with Espresso continue to use their own centralized sequencer but improve their users' experience by offering fast, reliable confirmations via Espresso.

Yes. Chains that are coordinating sequencing with other chains can still use Espresso independently of whether the entire collective does so and can opt in or out at any time.

There are three main ways to work with Espresso:

• Build on Espresso: Teams building rollups, app-specific chains, and other L2s/L3s can build upon Espresso’s base layer to benefit from fast confirmations, DA, or (optionally) decentralized sequencing. 
• Read from Espresso: Other chains, bridging protocols, exchanges, solvers, relayers, and others can read from Espresso to gain real-time insights into activities happening on integrated chains that they can safely act upon.
• Validate on Espresso: Node operators run Espresso software and participate in HotShot consensus. Espresso launched its mainnet in November 2024 with a permissioned set of 100 nodes, but an update planned for late 2025 will move the network to a permissionless proof-of-stake model.

At Espresso, we divide our efforts into two categories:

• Espresso Product: building production-ready infrastructure that enables chains to coordinate and achieve composability with each other in an incentive-compatible way.
• Espresso Research: exploring the design space of cross-chain composability, developing proposals for potential new products, and testing ideas with collaborators.

Some of the proposals and designs explored by Espresso Research include: crosschain builder marketplaces; shared sequencing; fast, secure crosschain message-passing; and aggregated interoperability clusters. For Espresso Research proposals, see here. For Espresso Research discussion, go to our forum.

Espresso is additive: Rollups can keep their existing architecture while gaining additional security and composability benefits. Instead of sending transaction batches directly to their settlement layer, integrated rollups send them to Espresso first, where its validators provide fast BFT confirmations before the batches continue to final settlement. A protocol-level restriction means only blocks that match the Espresso-confirmed blocks will settle on the L1. All rollups that integrate with Espresso also benefit from EspressoDA, which provides high-throughput, low-cost data availability. Additionally, some rollups opt to also use Espresso as a decentralized sequencer and/or for settlement.

The Espresso Network uses HotShot, a BFT consensus protocol that provides fast confirmations in a manner that is complementary to Ethereum’s consensus by making a different set of tradeoffs to optimize for speed. Specifically, HotShot is optimistically responsive, meaning it can support Web2 scale under normal networking conditions while sustaining Web3 levels of decentralization.

HotShot is derived from the HotStuff family of consensus protocols, but optimized for the specific needs of rollups, namely speed, security and enabling seamless crosschain interoperability. It’s also designed to scale to a validator set as large and geographically diverse as Ethereum's while reaching finality within seconds. For more on HotShot, check out the academic paper or read this post comparing it to Tendermint. 

Espresso provides a neutral base layer that any rollup can integrate with regardless of stack, VM, or even settlement layer. This universal base layer enables all chains to interoperate securely without compromising their sovereignty. Pre-existing applications that rely on crosschain messaging, such as bridges and intent systems, can plug in to the Espresso base layer to improve their latency and security.

Crosschain messages are only as secure as the confirmations backing them. Espresso enables more secure confirmations than those granted by centralized sequencers, without sacrificing on speed, and faster confirmations than the Ethereum L1, without sacrificing on security.

Crosschain messages based on Espresso confirmations thus allow applications that rely on crosschain message passing, such as bridges, to quickly settle bridge transactions without having to rely on single points of failure such as a centralized sequencer, and without having to wait 12 minutes for Ethereum to finalize the crosschain message. 

The Espresso System’s team works closely with other teams developing crosschain messaging protocols, such as Hyperlane and LayerZero, and spent significant time researching this topic. Learn more about our crosschain communication research here.

Espresso dramatically improves intent-based bridging by enabling solvers to act on secure confirmations within seconds rather than taking on sequencer or settlement risk. Today, intent-based bridges like Across rely on solvers who escrow funds on the source chain and pay users on the destination chain. Solvers typically risk getting rugged by acting on centralized sequencer confirmations to provide fast UX (rather than waiting for L1 settlement), pricing this risk into their fees.

With Espresso confirmations, solvers can reliably confirm escrow transactions within seconds using BFT consensus rather than trusting individual sequencers. This reduces solver risk, improves capital efficiency, and enables more competitive pricing for users. The faster, more secure confirmations also enable more efficient rebalancing for solvers. This is especially helpful for the longer tail of rollup applications whose centralized sequencers are deemed less trustworthy.

Espresso ensures that the transaction ordering over which a ZK proof has been generated can’t change. This means that applications verifying a ZK proof know there wont be any conflicting proofs in the future. Without a fast, secure base layer like Espresso, honest provers might generate valid ZK proofs over rollup data that never gets settled to Ethereum due to sequencer equivocation (e.g., a sequencer confirms for a user that their transaction is included in a block, but later excludes that transaction from the block it publishes to the L1).

Espresso’s fast, secure confirmations, as well as a protocol-level restriction preventing a rollup’s sequencer from equivocating, solves this by ensuring ZK provers always have access to the correct transaction data within seconds.

Espresso launched its Mainnet 0 in November 2024. It’s scheduled to upgrade to Mainnet 1 in Q4 2025, which will introduce permissionless proof-of-stake to the network. To get started using Espresso, see our docs here.

Get in touch with us here and check out our documentation here.

A permissioned set of node operators are currently running the Espresso Network.

Ultimately, Espresso's mainnet will be fully permissionless and you will be able to start running Espresso nodes by following our documentation. Our early docs for node operators can be found here. Feedback is welcome.

To get the benefits of Espresso as a user, you need to be using a chain or application that leverages Espresso. The chains that do so can be found here.

If the app or chain that you use does not yet use Espresso, you should let them know they should plug into the Espresso base layer by posting about it on Twitter or Farcaster and tagging Espresso. We are always welcoming more chains and applications to our growing ecosystem of projects that believe in a seamless, unified onchain user experience.

Espresso uses BFT (Byzantine Fault Tolerant) consensus, which guarantees security as long as fewer than one-third of validators act maliciously. An attacker would need to control over one-third of our decentralized validator set to compromise confirmations—a threshold that becomes increasingly expensive as the network grows.

Currently, Espresso's validators run HotShot consensus to provide cryptographic confirmations of block ordering and data. Protocol-level restrictions ensure that once Espresso confirms a block, integrated rollups can only publish matching blocks to their settlement layers.

In late 2025, Espresso will transition to proof-of-stake, requiring validators to stake tokens as collateral. This adds economic security on top of BFT consensus—attackers would need to control one-third of validators AND risk substantial economic value. This dual-layer model will make Espresso one of the most secure base layers in the blockchain ecosystem.

Check out the Quickstart Nitro Integration guide in our docs, join our developer community, or reach out directly to discuss your specific integration needs and timeline.

Visit our documentation, join our Discord community, or participate in our next Build & Brew hackathon to get hands-on experience building with Espresso confirmations.