Shared sequencer solution Espresso partners with Ethereum Layer-2 scaling solution Polygon Labs to develop AggLayer (aggregation layer) to solve rollup interoperability.
AggLayer was first introduced in January. It is designed to solve the fragmented liquidity problem in the blockchain space by centering UX scalability on a single, unified aggregation layer. AggLayer is similar to Risc Zero’s “Type 0” zkEVM, Zeth, a general-purpose programming language that can be EVM equivalent.
Both solutions are designed to enable cross-chain transaction verification. In the case of AggLayer, the protocol uses a process called proof aggregation to ensure that transactions across the ecosystems are valid.
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According to Polygon Labs documents, all transactions are guaranteed on AggLayer without relying on a third-party bridging solution.
In the long term, Polygon hopes that when a merge creates a destination chain message, it will also create a validity proof that immediately verifies its accuracy.
That’s a problem that Anurag Arjun, the founder of Avail, and his team hope to solve.
Arjun notes that while cross-chain communication is great for users who belong to the same ecosystem, once they leave the ecosystem they are likely to get a “substandard experience.”
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“If you really want to bring these rollups together, you need two things first and foremost,” Arjun told Blockworks. “You need an order proof – the order of transaction data – in the sense that if an aggregation has established a certain order of transactions, you need some guarantees for that. That’s what Avail validity proof is [data availability sampling] offers. And then you need the execution certificates, which are provided by the rollup itself.”
The distinction to make is that aggregating evidence in itself is not enough, and the order of transactions of these rollups is just as important, Arjun said.
“So if you combine order guarantees with the actual execution proof, then that’s why we’re able to do this orchestration – connecting these rollups,” he explained.
However, the current state of play is not yet as fast as real-time verification, and all interdependent rollups must be jointly created, merged, and verified before settling on Ethereum.
This is where Espresso comes into the picture. Espresso will be the coordinator that unifies the interdependent rollups before settling them on Ethereum.
Ben Fisch, CEO of Espresso Labs, described the collaborative efforts between Espresso and Polygon as critical to both ecosystems.
“Our respective teams have been thinking deeply about layer 2 interoperability over the past year – it’s amazing to see our solutions coming together in such a synergistic way. Polygon’s AggLayer and Espresso’s coordination layer are perfect complements,” Fisch told Blockworks.
Marc Boiron, CEO of Polygon Labs, shares this sentiment. He told Blockworks that he believes this new partnership will synergistically increase interoperability within Ethereum’s layer 2 environment.
“While the AggLayer ensures the integrity of data exchange between Ethereum Layer-2s, Espresso’s sequencing marketplace optimizes this process by enabling efficient coordination and fast transaction completion between multiple Ethereum Layer-2s,” said Boiron. “This integrated approach significantly improves the fluidity and user experience of transactions within Ethereum’s Layer-2 network.”
Espresso’s latest collaboration with Polygon on AggLayer shows the advancement of the modular approach to scaling Ethereum, an approach that contrasts with what the Nil Foundation, for example, is trying to achieve with sharded layer-2s.
Misha Komarov, the founder of the Nil Foundation, previously told Blockworks that it wants to take a protocol-level approach to interoperability by embedding the sequencer into the protocol so that it can send transactions between different shards.
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“So basically what it means is it keeps them all aggregated, it keeps them all together, it keeps the liquidity unified. It is as if there is no separation, there is actually no balkanization of ETH taking place,” Komarov said.
In simpler terms, the two approaches can be thought of as vertical versus horizontal scaling, although they combined features of both to varying degrees.
“ZkSync and Polygon aim for vertical scaling – layer-2 and layer-3 – [while] on our side, we aim for horizontal scaling,” he said. “We’re basically saying, okay, modularity can be done in a better way. Maybe it’s not even modularity anymore.”
Whichever approach ultimately prevails, there is widespread recognition that the fragmentation of UX and liquidity that currently prevails in many Ethereum scaling efforts is a barrier to adoption.
“This whole industry is a competition of ideas,” Komarov adds. “A competition of who has the best idea and who gets there first – its implementation – is taking over the market.”
Macauley Peterson contributed reporting.