Espresso, a blockchain project focused on cross-chain composability and backed by venture capital firm Andreessen Horowitz, has announced that its confirmation layer is now live on mainnet.

The launch follows two years of research and development, five testnets, and integration plans with more than 20 chains. This milestone marks significant progress for the team as they work towards “making Ethereum (ETH) composable again,” the Espresso Systems team said in the announcement.

Espresso notes that its confirmation layer provides the infrastructure for chains to interact quickly and reliably, allowing rollups to achieve synchronous composability. This layer enables two composable chains to confirm their respective state transitions by reading each other’s transaction data.

“To achieve synchronous composability, chains need a shared source of truth they can use to quickly and reliably confirm the state transitions of other chains,” Espresso wrote.

According to the Espresso team, several ecosystem partners are prepared to integrate the confirmation layer. These partners include bridges, chains, stack providers, and Rollups-as-a-service (also known as RaaS) platforms.

Specific partners include Linux-powered rollups platform Cartesi, modular zero-knowledge stack chains Airchains, and Arbitrum creators OffChain Labs. Additional partners are bridge platform Across Protocol and RaaS provider AltLayer.

Espresso plans to roll out the mainnet in phases, gradually deploying functionality, onboarding launch partners, and decentralizing the node operator set. A roadmap outlines the main components scheduled for release throughout 2025.

The Espresso team raised $28 million in a series B round in March, led by VC platform a16z Crypto.