Espresso is the foundational interoperability layer for Ethereum, offering fast confirmations for cross-chain transactions. And now it is opening up for anyone to participate in running the network.

Last Friday, April 25, 2025, Espresso Systems, a core contributor to the Espresso community, along with 22 node operators successfully upgraded Decaf, the Espresso Network’s long-running testnet, to a permissionless version of HotShot proof-of-stake consensus.

This upgrade marks a major milestone in our journey toward a fully permissionless confirmation layer that unites Ethereum's fragmented ecosystem. Various technical improvements will also further speed up confirmation times for chains using Espresso.

Why This Matters

Since launching on mainnet in November 2024, the Espresso Network has operated with a permissioned set of 22 community and institutional node operators running 100 nodes across six continents. While this approach has provided stability during our initial phase, which we called Mainnet 0, true decentralization requires opening participation to anyone willing to stake.

This latest upgrade to the Network’s long-running testnet (Decaf) allows for thorough testing before bringing it to production on mainnet. Mainnet 1, anticipated later this year, will represent a critical step toward our vision of a permissionless, trust-minimized confirmation layer that can serve as the backbone for crosschain composability across Ethereum's fragmented L2/L3 ecosystem.

This initial upgrade will see Espresso Systems allocate testnet stake across the 22 node operators that have been running the network over the last six months. When sufficient testing has been completed with this more limited group, Espresso Systems also plans to delegate testnet stake to new operators looking to get started running Decaf.

If you have experience running nodes for proof-of-stake networks and you are interested in participating in Espresso’s testnet, you can learn more about registering a staking node on Espresso Systems’ documentation site and get started with the Espresso Network’s staking CLI. Please stay tuned for future announcements about updates to Decaf and delegation of testnet stake on X and Discord.

Technical Improvements Beyond PoS

The Decaf upgrade delivers more than just a new consensus mechanism. The team at Espresso Systems also made technical upgrades that we anticipate will speed up the confirmation times chains can expect from the Espresso Network. For instance, the HotShot consensus protocol has been updated to reduce the number of rounds it takes to finalize a block by one (from four to three rounds). The Espresso Systems team also enhanced the verifiable information dispersal (VID) protocol, which optimizes how block data is processed across the network. Rather than requiring each storage node to download complete blocks, VID intelligently distributes erasure-coded chunks of data, dramatically improving network efficiency.

In a development environment, the HotShot upgrade and VID improvements have demonstrated substantial performance gains, and we anticipate they'll reduce confirmation times on Decaf by approximately 29%. This means even faster crosschain communication for L2s and L3s integrating with Espresso.

What's Next

Decaf’s testnet upgrade serves as a dress rehearsal for our upcoming mainnet PoS deployment, anticipated later in 2025.

The upcoming transition to Mainnet 1 will coincide with the launch of the Espresso Network’s native token ($ESP), which will power the network's economic security model and governance system. We’ll be releasing more details about the token and PoS-update schedule in the coming months via official channels, including the Foundation’s X account. This will include details for new node operators who are interested in joining and running a node in the Espresso Network in the future.

Over the coming weeks, we will announce next steps for node operators who would like to start running Espresso’s Decaf testnet in preparation for Mainnet 1. This collaborative testing phase is essential to ensuring a smooth mainnet transition.

We also want to thank our node operators who have helped secure the Espresso Network up to this point. We look forward to recognizing them for their contributions via a mainnet delegation program for which we will share details in the near future.

The Bigger Picture

The Espresso Network was designed from the ground up to solve the fragmentation challenges facing Ethereum's expanding L2 and L3 ecosystem. By providing fast, secure confirmations backed by Byzantine fault-tolerant (BFT) consensus, Espresso enables chains to trust and act on information from each other in seconds rather than minutes or days.

With the Decaf PoS upgrade, we're one step closer to delivering a confirmation layer with economic security, but optimized for speed and crosschain interoperability.

Join us on this journey as we work to unite Ethereum and enable the next generation of crosschain applications.

Get Involved

Those interested in Espresso have several options to stay connected and learn more:

• Discord – The primary community hub and place for technical discussions

• Newsletter (launching soon) — Sign up for key updates on grants, governance, and development

• Espresso Systems’ blog — Updates from the original developers of the Espresso technology

• Follow the Espresso Foundation and Espresso Systems on X

The Espresso Foundation is committed to building a sustainable, decentralized future where all chains act like one while retaining their sovereignty and speed—and we’re excited to take this next step together.

More details coming soon.