Espresso helps rollups:
Scale
01
Decentralize
02
Interoperate
03
Espresso is designed to offer rollups a means of achieving credible neutrality, enhanced interoperability, & long-term alignment with Ethereum.
A shared sequencing marketplace and finality gadget connecting layer-2 scaling solutions
Scale without
compromise
Espresso's HotShot finality gadget is optimistically responsive and guarantees fast transaction finality and throughput limited only by network bandwidth.
Perfectly paired
with Ethereum
HotShot scales to tens of thousands of nodes while maintaining strong performance to enable participation of Ethereum’s full validator set.
Interoperability
at its best
Espresso allows proposers to bid for blockspace across multiple rollups, making cross-chain messaging and bridging cheaper, faster, and safer.
Espresso for
L2 Rollups
Accelerate your decentralization roadmap, inherit security from Ethereum, and interoperate more reliably with other rollups—without sacrificing on value accrual or sovereignty.
Participate as L2 Rollup
Espresso for
App Developers
Offer app developers more reliable and neutral infrastructure. No more single points of failure.
Espresso for
End Users
No compromises. High performance, low (and fair) fees, a diversity of applications, and no lock-in.
Monolithic
Today’s rollup teams develop and maintain all components as a singular package - not modular systems that could easily be swapped or upgraded.
Siloed
Rollups operate in their own silos, introducing all the same issues of interoperability that L1s have experienced.
Centralized
From sequencing to execution and proving, today's rollups are all run and maintained by their own teams - sacrificing credible neutrality and monopoly-resistance.
Shared sequencing
Many rollups leverage the benefits of the Espresso Sequencer, creating efficiencies for interoperability & beyond.
Decentralization
A permissionless network of nodes running the Espresso Sequencer offers robust data availability and transaction ordering.
SCALE
HotShot Consensus is optimistically responsive, so rollups don't compromise on high throughput or fast finality.
Easy integration
The Espresso Sequencer is designed to work seamlessly with existing rollup frameworks and other modular systems.
Proposer-Builder Separation
Espresso Sequencer is designed to be compatible with proposer-builder separation, a paradigm that supports mitigation of the harmful effects of MEV.
Agnostic Ordering
Designed to work with any approach to transaction ordering, from First Come First Serve to MEV-optimized.
Cross-Rollup Building
Block builders across multiple rollups only need to coordinate with one proposer, enabling them to guarantee order and outcomes.
Execution and Outcomes
With block builders integrated, users will receive guarantees of transaction inclusion and execution across multiple rollups.
Participate as
L2 Rollup
If you are building a rollup, we want to work with you.
For support in integrating with us, get in touch here.
Participate as Node Operator
If you’d like to help secure Espresso and have experience running node infrastructure, please reach out.
News & Brews
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Article
Releasing Testnet 5: Cappuccino

Espresso has expanded the HotShot finality layer to 100 nodes on Cappuccino testnet. The testnet also adds support for Arbitrum fraud proofs.

Ethereum’s infinite garden powers thousands of decentralized applications. Major L2s now consistently see more transaction activity than the Ethereum L1. The number of customizable application-specific chains is continuously growing as developers opt for the flexibility and sovereignty of their own execution environment. But as rollups offer scale and customizability, they are also working to maintain the composability and credible neutrality of the L1 to stay true to Ethereum’s ethos.

This is why we prioritized further decentralization in Espresso’s fifth testnet, Cappuccino. HotShot, Espresso’s fast finality layer, will now decentralize to a network of 100 geographically distributed nodes — a crucial step as we move towards a fully permissionless system. We’ve also added support for Arbitrum fraud proofs, ensuring that Espresso will be production-ready for Arbitrum Orbit chains as it nears a mainnet release.

This release is available to the public. The code we have developed to add support for Arbitrum fraud proofs is available on GitHub. As a part of this release, we have also published documentation that will enable developers and users alike to interact with Cappuccino.

If you are building a rollup, you can get started on your integration with the latest Espresso testnet here and reach out to collaborate with us here.

HotShot & The Espresso Marketplace

Cappuccino testnet is focused on HotShot — Espresso’s optimistically responsive consensus protocol, designed to support the scale that rollups offer while maintaining strong security and decentralization. HotShot is a fast finality layer that rollups can share for much quicker confirmations than the Ethereum L1 provides. As such, HotShot enables fast bridging and more seamless interoperability between rollups. No longer will users have to deal with long, uncertain wait times when moving assets from one L2 to another.

Espresso’s fast finality layer is a complement to the Espresso Marketplace design. The Espresso Marketplace enables rollups to sell their “sequencing rights” — or the right to order the transactions submitted to their system. Proposers (or “sequencers”) bid via the marketplace for this right and can include and order transactions across an arbitrary number of rollups at once. Rollups, meanwhile, can opt into and out of selling their sequencing rights on the marketplace at any time — including setting a “reserve price” or a minimum threshold that must be bid. The Espresso Marketplace will be implemented in upcoming releases.

Cappuccino running on 100 geographically distributed nodes

We are collaborating with Blockdaemon, Informal Systems, KudasaiJP, LinkPool, P2P, Sub7, ZK Validator, Figment, Nethermind and Unit410 to support us in running 100 geographically distributed nodes for HotShot consensus across 6 continents.

Decentralizing Espresso’s finality layer supports more secure rollup preconfirmations. This has various positive downstream implications — for instance, the time it takes to bridge from a rollup using HotShot as a finality gadget can be reduced to just seconds. This is exemplified by our recent demo in collaboration with Across Protocol.

This work follows our last testnet, Gibraltar, whose nodes were run by one external operator, Blockdaemon, and Espresso Systems.

Adding support for Arbitrum fraud proofs

Our previous testnet, Gibraltar, unveiled Espresso’s integration with the Arbitrum Nitro stack. Our team has continued to build upon this integration by adding support for Arbitrum fraud proofs.

This means that Arbitrum Orbit chains that integrate with Espresso will maintain the full security provided by the Arbitrum stack. It also paves the way to add further support for BOLD, which will make submitting Arbitrum fraud proofs completely permissionless.

Our work in the Arbitrum ecosystem continues to mature and stabilize in preparation for a production launch. These development efforts also support our work with Offchain Labs around decentralized Timeboost, a transaction ordering protocol that is complementary to Espresso.

If you’re building an Arbitrum Orbit chain, and want to leverage the fast preconfirmations that Espresso’s finality layer has to offer, please get in touch with us here.

In partnership with Caldera and AltLayer, we will soon have demo Arbitrum-stack rollups running on Cappuccino for test deployments and transactions. Stay tuned for updates.

Join the Espresso Ecosystem

With four rollup stack integrations now supported by Espresso, we’re looking forward to showcasing how HotShot’s decentralized consensus supports near-instantaneous preconfirmations for rollup users, bridging protocols, and other cross-rollup use cases.

Be sure to follow along on Twitter/X, on Farcaster, and at our website for further updates on Cappuccino and the Espresso roadmap.

If you’re interested in deploying on the Cappuccino testnet, please get in touch with us here.

Article
Releasing Testnet 5: Cappuccino

hainReleasing Testnet 5: Cappuccino

Espresso has expanded the HotShot finality layer to 100 nodes on Cappuccino testnet. The testnet also adds support for Arbitrum fraud proofs.

Ethereum’s infinite garden powers thousands of decentralized applications. Major L2s now consistently see more transaction activity than the Ethereum L1. The number of customizable application-specific chains is continuously growing as developers opt for the flexibility and sovereignty of their own execution environment. But as rollups offer scale and customizability, they are also working to maintain the composability and credible neutrality of the L1 to stay true to Ethereum’s ethos.

This is why we prioritized further decentralization in Espresso’s fifth testnet, Cappuccino. HotShot, Espresso’s fast finality layer, will now decentralize to a network of 100 geographically distributed nodes — a crucial step as we move towards a fully permissionless system. We’ve also added support for Arbitrum fraud proofs, ensuring that Espresso will be production-ready for Arbitrum Orbit chains as it nears a mainnet release.

This release is available to the public. The code we have developed to add support for Arbitrum fraud proofs is available on GitHub. As a part of this release, we have also published documentation that will enable developers and users alike to interact with Cappuccino.

If you are building a rollup, you can get started on your integration with the latest Espresso testnet here and reach out to collaborate with us here.

HotShot & The Espresso Marketplace

Cappuccino testnet is focused on HotShot — Espresso’s optimistically responsive consensus protocol, designed to support the scale that rollups offer while maintaining strong security and decentralization. HotShot is a fast finality layer that rollups can share for much quicker confirmations than the Ethereum L1 provides. As such, HotShot enables fast bridging and more seamless interoperability between rollups. No longer will users have to deal with long, uncertain wait times when moving assets from one L2 to another.

Espresso’s fast finality layer is a complement to the Espresso Marketplace design. The Espresso Marketplace enables rollups to sell their “sequencing rights” — or the right to order the transactions submitted to their system. Proposers (or “sequencers”) bid via the marketplace for this right and can include and order transactions across an arbitrary number of rollups at once. Rollups, meanwhile, can opt into and out of selling their sequencing rights on the marketplace at any time — including setting a “reserve price” or a minimum threshold that must be bid. The Espresso Marketplace will be implemented in upcoming releases.

Cappuccino running on 100 geographically distributed nodes

We are collaborating with Blockdaemon, Informal Systems, KudasaiJP, LinkPool, P2P, Sub7, ZK Validator, Figment, Nethermind and Unit410 to support us in running 100 geographically distributed nodes for HotShot consensus across 6 continents.

Decentralizing Espresso’s finality layer supports more secure rollup preconfirmations. This has various positive downstream implications — for instance, the time it takes to bridge from a rollup using HotShot as a finality gadget can be reduced to just seconds. This is exemplified by our recent demo in collaboration with Across Protocol.

This work follows our last testnet, Gibraltar, whose nodes were run by one external operator, Blockdaemon, and Espresso Systems.

Adding support for Arbitrum fraud proofs

Our previous testnet, Gibraltar, unveiled Espresso’s integration with the Arbitrum Nitro stack. Our team has continued to build upon this integration by adding support for Arbitrum fraud proofs.

This means that Arbitrum Orbit chains that integrate with Espresso will maintain the full security provided by the Arbitrum stack. It also paves the way to add further support for BOLD, which will make submitting Arbitrum fraud proofs completely permissionless.

Our work in the Arbitrum ecosystem continues to mature and stabilize in preparation for a production launch. These development efforts also support our work with Offchain Labs around decentralized Timeboost, a transaction ordering protocol that is complementary to Espresso.

If you’re building an Arbitrum Orbit chain, and want to leverage the fast preconfirmations that Espresso’s finality layer has to offer, please get in touch with us here.

In partnership with Caldera and AltLayer, we will soon have demo Arbitrum-stack rollups running on Cappuccino for test deployments and transactions. Stay tuned for updates.

Join the Espresso Ecosystem

With four rollup stack integrations now supported by Espresso, we’re looking forward to showcasing how HotShot’s decentralized consensus supports near-instantaneous preconfirmations for rollup users, bridging protocols, and other cross-rollup use cases.

Be sure to follow along on Twitter/X, on Farcaster, and at our website for further updates on Cappuccino and the Espresso roadmap.

If you’re interested in deploying on the Cappuccino testnet, please get in touch with us here.

Article
Espresso is solving rollup interoperability with the AggLayer and Polygon Labs

Together, the AggLayer and Espresso solve the biggest challenge facing the rollup-centric roadmap: interoperability.

We’re bullish Ethereum L2s.

L2s are successfully taking execution off-chain and horizontally scaling Ethereum. It’s clear from ever-increasing metrics that users enjoy the lower fees and improved user experience provided by these protocols. Transaction count and total value locked have also grown exponentially over recent years (see L2BEAT). The speed of innovation around the L2 landscape is unprecedented, with new solutions coming to market every week.

But, Ethereum didn’t have the coordination layer to ensure that these new L2s could seamlessly interoperate with each other. Currently, users must move between fragmented execution environments, fracturing the composability they’re accustomed to on the Ethereum L1. Users also face long times for simple tasks such as bridging, which can take several minutes for deposits and up to several days for withdrawals.

Coordinated sequencing and fast trustless message passing using zk-proofs are foundational building blocks towards improved composability. Ethereum Foundation researcher Justin Drake recently highlighted how these approaches solve rollup fragmentation, thus supporting a more unified scaling roadmap for Ethereum.

Espresso and the AggLayer are perfect complements to enhance rollup interoperability

Our mission at Espresso is to maximize the value layer-2 rollups capture, while ensuring they optimize the ability to satisfy user requests. This should be seamless even when users wish to interact with multiple rollups simultaneously and interdependently. This is why we are coordinating development efforts with Polygon Labs, the developers of Polygon PoS, Polygon zkEVM, Polygon CDK, and the AggLayer. The focus of this work will be on the development of the AggLayer and how it will be supported, and enhanced, by Espresso’s sequencing marketplace and fast-finality layer.

The AggLayer can support faster, more secure bridging and near-synchronous composability between rollups. It does so through enabling rollups to securely pass messages to each other while ensuring that the inputs on one chain are valid outputs from another chain. Multiple rounds of messages can be passed before settlement on Ethereum. Transactions on each of the rollups may be dependent on these messages. Unlike prior “bridging” solutions, these transaction dependencies are guaranteed by the AggLayer without trusted intermediaries. When a rollup creates a message output destined for other rollups it will also create a validity proof of its correctness. If it could do so in real time, the receiving rollup could simply verify the proof while interpreting the message; however, the state of proving is not sufficiently fast yet. The beautiful insight of the AggLayer is that the creation of these proofs can be delayed until all interdependent rollup blocks are created, and then aggregated and verified jointly at the same time the blocks are posted and settled on Ethereum.

However, while the AggLayer provides security for cross-rollup message passing, these interdependent rollup blocks don’t magically manifest on their own — that requires coordination. This is what the AggLayer leaves up to an emergent coordination layer. Enter Espresso.

Espresso provides a sequencing marketplace through which specialized service providers (sequencers) can purchase the right to coordinate the block construction of multiple rollups at the same time. This right may be short-lived or longer-term and can easily change hands. The sale proceeds go directly to the rollups involved and only if they clear a minimum price set by each rollup. Sequencers that can generate surplus value through coordinating block construction for multiple chains are best positioned in the market to successfully clear these prices, above and beyond what rollups can gain sequencing on their own. One way to do so for AggLayer-compatible rollups is to fill this key coordination role that AggLayer-secure message passing requires. Additionally, Espresso provides a fast confirmation service, HotShot, that allows users to know the results of their cross-rollup transactions before Ethereum settlement (aka fast finality).

In short, these technologies significantly improve Ethereum’s user experience and security when leveraged together. Our teams will be working together to maximize the compatibility of Espresso and the AggLayer, ensuring that all Ethereum L2s will be able to leverage both technologies for improved composability.

Towards a better Ethereum

We’ll be updating the community on our plans to further integrate the Polygon technology stack with Espresso.

We will post regular updates on our progress in this thread on the Polygon community forums. We will also be hosting a Twitter Spaces with the Polygon Labs team on [date] to discuss next steps related to these development efforts.

If you are a rollup or application developer interested in leveraging the AggLayer and Espresso, you can get in touch with us here.

Article
Partnering with 10 node operators to decentralize Espresso’s Cappuccino testnet

Espresso will be decentralizing the set of nodes running HotShot consensus in its upcoming testnet, Cappuccino, to be released later this month. This is an important milestone on Espresso’s journey of steadily growing the operator set leading up to mainnet — with HotShot’s ultimate goal being to encompass the distribution and staked capital of the entire Ethereum validator set.

In our latest testnet, Gibraltar, we partnered with Blockdaemon, which ran 4 HotShot nodes across Asia and Europe, in addition to those operated by Espresso Systems. With Blockdaemon’s support, Espresso was the first platform for rollup sequencing running with external node operators on testnet.

Deploying Espresso testnets on multiple nodes run by a diverse group of node operators is an important step towards readying the Espresso infrastructure for a production launch. As part of this, our next testnet, Cappuccino, will be run on 100 nodes that are geographically distributed across 6 continents.

Decentralizing HotShot for the Cappuccino testnet

Espresso has two core components. The first is a sequencing marketplace, where rollups sell slots to participating sequencers. The second is a consensus protocol that functions as a finality layer. The finality layer supports the marketplace and can also be leveraged independently.

A sequencer participating in the Espresso marketplace may bid for the opportunity to sequence blocks for multiple rollups at once — allowing them to facilitate cross-rollup activity, among other advantages. A rollup may have a default sequencer, which produces blocks for the rollup in the event that the sequencing opportunity isn’t sold. The marketplace maximizes economic efficiency within the entire rollup sequencing space and the value that rollups are able to capture..

The finality layer of Espresso is powered by HotShot. This is a BFT consensus protocol that provides users (or external entities including bridges, exchanges, etc.) with fast preconfirmations, or assurances that transactions will not be reversed, and will eventually be reflected on the Ethereum L1. HotShot is an optimistically responsive network, which means it can produce blocks as quickly as the network allows and reach finality within seconds, while scaling to thousands of operators. Expanding and diversifying the HotShot operator set in Cappuccino will help us continue to push the envelope on Espresso’s performance and security.

How we selected partner node operators

In February, we announced an open application process for node operators interested in running HotShot nodes for the Cappuccino testnet. After engaging with over 600 node operators, we were able to select 10 operators who will be running HotShot nodes for Cappuccino: Blockdaemon, Figment, Informal Systems, KudasaiJP, LinkPool, Nethermind, P2P.org, Sub7, Unit 410, and ZKValidator.

In this selection process, we prioritized operators in a range of locations to improve geographical diversity of the network and could support several cloud and bare metal environments. We also decided to work with experienced and highly technical operators who will help us to further define our node operator onboarding process and industry best practices. This is crucial as we look to create a smooth onboarding process for future operators, including those who join the HotShot network when it becomes fully permissionless.

These Cappuccino operators will collectively run 100 HotShot nodes for the testnet, spanning six continents.

Future plans towards permissionlessness

With Cappuccino, Espresso will be the first platform for shared sequencing run on a distributed set of over 100 nodes. This paves the way to a credibly neutral decentralized network that will support rollup interoperability and security, while maintaining high performance.

We’re looking forward to running the Cappuccino testnet with our partners and building the supporting infrastructure to create a united Ethereum. If you’re a rollup interested in deploying on Espresso, please get in touch with us here.

We’re grateful for the time and effort contributed by our partners in support of the Cappuccino testnet, especially those who participated in the open call for node operators. Please note that although we will not be able to respond to all applicants individually, we will share progress updates and selection decisions via Twitter/X and in our Discord server via the #node-operators-updates channel. We will continue to update the recommended technical specifications for running a node in our documentation.

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