Launching Espresso Systems’ Cortado Testnet to the Public
Espresso Systems and Caldera co-deploy Vienna, an OP Stack rollup integrated with the third testnet of the Espresso Sequencer. The Cortado Testnet can sequence transactions for this OP Stack rollup as well as the Polygon zkEVM-based rollup integrated in the previous testnet.
Today we are unveiling the first live, public demo of a shared sequencer, supporting not only multiple rollups but multiple different rollup stacks. With this milestone, we are taking the first strides toward the Espresso Sequencer serving as a neutral, open layer that can connect across all L2s, regardless of stack or ecosystem.
With this release, we are excited to launch a public testnet for Espresso Sequencer Testnet 3: Cortado, seamlessly integrating both an OP Stack rollup and Polygon zkEVM rollup for decentralized, shared sequencing.
As a part of this latest public testnet, we have been working with Caldera on the deployment of Vienna, an OP Stack rollup integrated with the Espresso Sequencer for decentralized, shared sequencing. Our collaboration with Caldera is an early demonstration of the ease at which rollup operators will be able to integrate with the Espresso Sequencer. In addition to the core rollup node, Caldera’s infrastructure includes a bridge UI, testnet faucet, and block explorer. You can get started using all of these components at the testnet’s public homepage.
Along with this public release, we’re releasing documentation on how users can interact with Cortado, and sharing next steps for the Espresso Sequencer.
The release also sees a number of improvements to the Espresso Sequencer protocol. With every testnet release, the Espresso Sequencer’s consensus protocol, HotShot, becomes more reliable. Notably, Cortado now supports a catchup mechanism, which allows nodes to come back online after an arbitrary number of views has passed since it last was online.
Supporting shared sequencing with the Polygon zkEVM and OP Stacks
With the OP Stack integration in Cortado, testnet users can submit transactions for both the OP Stack and Polygon zkEVM rollups integrated with the Espresso Sequencer. This means the Espresso Sequencer is now a shared sequencer between two distinct rollup stacks, and users of both stacks can enjoy the fast pre-confirmations the Espresso Sequencer offers.
We’ve created a video demo that showcases a user submitting a transaction through MetaMask, which is then propagated through Espresso Sequencer nodes. The transaction is then included in a block sequenced by HotShot. For the Polygon zkEVM demo, after the transaction is ordered and included in a rollup block, it is sent to Polygon zkEVM nodes and provers. In the OP Stack rollup demo, the transaction is committed to the L1 testnet after the transaction is ordered and included in a rollup block.
If you’d like to try submitting transactions or deploying contracts to either rollup stack on the public Cortado testnet, you can head to our documentation site where we outline the process to get started. You can also build and run your own local devnet of Cortado by following the steps on the op-espresso-integration repo.
Next steps
Over the last two months, we’ve been working with a number of rollup and rollup-as-a-service teams to integrate with the Espresso Sequencer. A number of those collaborations have resulted in demo integrations, and we will soon share those via our community channels.
We also announced a partnership with Offchain Labs to bring decentralized and shared sequencing to Ethereum rollups. Our collaboration will see both teams jointly research and develop Timeboost, a transaction-ordering design proposed by Offchain Labs. Offchain Labs is also supporting us in building integrations between the Arbitrum technology stack, Timeboost, and the Espresso Sequencer.
In our next testnet, we will be integrating verifiable information dispersal (VID) and a peer-to-peer fallback network into HotShot, increasing resilience and robustness. To stay up to date on this progress, you can follow the HotShot repository on GitHub.
We’re excited to make this testnet public, and are looking forward to users interacting with Vienna, the OP Stack rollup co-deployed with Caldera. If you’re interested in integrating with the Espresso Sequencer, please get in touch with us.
