First shared sequencer tech to go live on Polygon zkEVM testnet

The testnet, dubbed Doppio, will be open to external nodes over the next few months

article-image

Satheesh Sankaran/Shutterstock modified by Blockworks

share

Blockchain infrastructure company Espresso Systems has released a testnet version of the Espresso Sequencer on a forked version of Polygon zkEVM.

The testnet, named Doppio, has been operating within the company and will be open to external nodes over the next few months.

Sequencers are responsible for ordering transactions from the mempool and then sending the information back to a virtual machine. Similar to validators on a layer-1 network, they play a critical role in operating layer-2 blockchain networks.

Today, sequencers remain relatively centralized. Rollups run their own siloed sequencers with their own execution environments — and in the case of zero-knowledge (ZK) rollups, they also have their own provers.

In an interview with Blockworks, co-founder and strategy lead at Espresso Jill Gunter explained that existing sequencers operate in a relatively monolithic way.

“In existing rollup solutions, the sequencer is just a component bundled with the rest of the rollup software,” Gunter said. “Nothing is programmable, upgradable or swappable in a very easy way.”

As a result, many rollups today have experienced some type of downtime, something Gunter believes is downplayed in today’s rollup environment.

“It’s not a total disaster because you can always force the transaction back to the [layer-1],” she said. “But that might be prohibitively expensive, and cause what I call soft censorship issues where the transactions are not being prioritized.”

How does espresso’s decentralized sequencer work?

Espresso has designed its very own specialized proof-of-stake system — HotShot — that will be used to optimize for the right balance of performance while remaining decentralized and robust, Gunter explains.

“It is a distributed consensus system that can be shared among different rollups, so no longer will a rollup have to have the sequencer bundled within their own software stack. They will be using the Espresso [application programming interface] to call and submit transactions to the Espresso sequencer,” she said.

The Espresso sequencer does two things: It performs data availability as an option — this means that if a rollup wants data availability as something that is additive, they can. It also performs consensus on the order of transactions. 

“The Espresso sequencer can do this across multiple rollups and there’s all kinds of interesting things that happen when you start having cross rollup ordering,” Gunter said. “There’s potential for cross rollup MEV — which we think can be a source of revenue for those who are participating in the Espesso network and the [layer-2s] as well.”

Source: Espresso Systems

The team is also planning to leverage ETH staking to ensure there is economic alignment with Ethereum layer-1 — this is currently in the works with Eigenlayer. 

Following the testnet launch on Polygon zkVM, Gunter notes that Espresso is also working on a partnership with Caldera to build an integration between the Espresso Sequencer and the OP stack. There are also existing agreements with Spire, Injective and Catalyst AMM to support them in prioritizing integration with Espresso’s Sequencer.


Get the news in your inbox. Explore Blockworks newsletters:

Tags

Upcoming Events

Old Billingsgate

Mon - Wed, October 13 - 15, 2025

Blockworks’ Digital Asset Summit (DAS) will feature conversations between the builders, allocators, and legislators who will shape the trajectory of the digital asset ecosystem in the US and abroad.

Industry City | Brooklyn, NY

TUES - THURS, JUNE 24 - 26, 2025

Permissionless IV serves as the definitive gathering for crypto’s technical founders, developers, and builders to come together and create the future.If you’re ready to shape the future of crypto, Permissionless IV is where it happens.

Brooklyn, NY

SUN - MON, JUN. 22 - 23, 2025

Blockworks and Cracked Labs are teaming up for the third installment of the Permissionless Hackathon, happening June 22–23, 2025 in Brooklyn, NY. This is a 36-hour IRL builder sprint where developers, designers, and creatives ship real projects solving real problems across […]

recent research

Unlocked by Template (7).png

Research

Union’s improvements upon Tendermint consensus through CometBLS, coupled with ZK proving through Galois, allow for a broadly scalable, cost efficient, and low latency IBC implementation that is feasibly scalable across every existing blockchain, virtual machine and runtime. The implementation offers modular crosschain interoperability without the need for trusted intermediaries.  

article-image

Kraken’s chief security officer Nick Percoco said the exchange turned the tables on a North Korean hacker

article-image

Or is it approximately the least cypherpunk thing we could do?

article-image

Over 20% of SOL-USD swap volume goes through SolFi

article-image

CEO Vlad Tenev calls expected clarity on listing crypto asset securities “a big opportunity”

article-image

Big Tech pulled US indexes back into the green Thursday, as investors waited for two more Mag 7 first-quarter reports after the bell

article-image

Charts and takeaways from Tuesday’s jobs report and Wednesday’s GDP print, as the economy digests the tariff war