Espresso Systems and Caldera Bring Decentralized Sequencing to OP Stack

Espresso Systems
3 min readJul 20, 2023


The organizations will work together to integrate the Espresso Sequencer with the OP stack, utilizing Caldera’s platform

We are excited to announce our upcoming contributions to the OP ecosystem with Caldera, a rollup-as-a-service (RaaS) company that enables developers to deploy custom-built rollups for on-chain applications. We’ll collaborate to develop an integration between the Espresso Sequencer and the OP stack. This integration also creates a path towards Caldera layer 2s (L2s) taking advantage of the Espresso Sequencer’s support for decentralization, scale, and interoperability.

Over the coming months, Espresso Systems and Caldera will deploy an optimistic rollup that uses the Espresso Sequencer for ordering and fast confirmations and Espresso Data Availability (DA) for storage. Caldera will provide the OP rollup interface, site hosting, block explorer and indexers. The Espresso Sequencer will integrate with the OP stack, to support developers in building decentralized rollups from launch and accelerating the Superchain vision. An upcoming testnet will make it easy for anyone to test this new OP chain and see how transactions are sequenced by the Espresso Sequencer. Future developers building on Caldera will be able to easily opt into using the Espresso Sequencer and Espresso DA as a plug-in component of the modular rollup stack.

The Espresso Sequencer and Espresso DA both leverage HotShot, a consensus protocol specifically designed to enable robust decentralization without compromising on the fast, low-fee user experience that users have come to expect from rollups. HotShot achieves this through optimistic responsiveness. You can read more in our blog post or our paper on our approach to consensus here and here.

Caldera enables developers to easily build dedicated blockchains for their applications. Through its ecosystem, Caldera chains are interoperable while also being EVM compatible. Caldera simplifies the process of launching a blockchain by providing everything needed to run a rollup: an interface, site hosting, spinning up block explorers, indexers, and oracles. Caldera has also curated a select ecosystem of recommended bridges and more, which lessens the lift to launch an L2.

We are building the Espresso Sequencer so that it can support any rollup framework or architecture. On the heels of unveiling our first zk-rollup integration, we are thrilled to share that our next testnet project, alongside Caldera, is to prioritize optimistic rollup frameworks — starting with the OP Stack. By combining the Espresso Sequencer and Espresso DA with Caldera’s infrastructure, developers have an opportunity to build dedicated blockchains for their applications, without trading off decentralization for performance.

If you are building on the OP Stack and interested in getting early access to integrate with the Espresso Sequencer, we would love to hear from you. Head to our website at and get in touch via the “Participate” link.

And, in case you missed it, our proposal to build the OP Stack’s Leader Election proof-of-concept was accepted. We’re thrilled to be contributing to the OP Stack and the Superchain, and are excited to work through these processes with Caldera.

About Caldera

Caldera specializes in building high-performance, customizable, and application-specific layer-two blockchains. These custom-built blockchains (Caldera Chains) offer high throughput, low latency, and customizable features for optimizing the performance and user experience of decentralized applications. Caldera is backed by backers like Dragonfly, Sequoia, Ethereal Ventures, and Zonff Partners.

About Espresso Systems

Espresso Systems are the developers of the Espresso Sequencer, supporting the decentralization of rollups in the Ethereum ecosystem and beyond. Espresso Systems has raised over $30mm from backers like Electric Capital, Greylock Partners, Sequoia Capital, and Polychain Capital.



Espresso Systems

We are the lead developers of the Espresso Sequencer, which supports rollups with decentralization, scale, and interoperability.