Compose: A composability layer solving a critical challenge for Ethereum - fragmentation. This blog post will introduce you to Compose, the problems it solves, and why it’s critical to keep Ethereum healthy.
Ethereum’s composability and network effect are the foundations that unlocked DeFi, DAOs, DeSci, and other groundbreaking primitives. But as Ethereum scaled through rollups, something else inadvertently happened: fragmentation.
Today, rollups operate like isolated islands: liquidity pools are siloed, DeFi protocols can’t interact atomically and introduce wait times, and users are pushed through costly, limited, and slow bridges. Meanwhile, developers need to rebuild the same dApps or infrastructure across every rollup, trying to capture fragmented value; in the process also fragmenting their own user bases. All this culminates in a stark contrast to the composable Legos that exist on the L1.
The network effects that once made Ethereum unstoppable are breaking down.
Until now…
Enter Compose: A composability layer solving a critical challenge for Ethereum — fragmentation.
The problems holding Ethereum back
Fragmented liquidity and user experience: Assets and users are scattered across rollups. A simple action like borrowing on one rollup and swapping on another turns into a delayed, multi-step ordeal.
Broken composability: On Ethereum L1, contracts can call each other atomically within a single block. On rollups, composability is asynchronous — messages take minutes or days, exposing users and protocols to risk and wait times.
Bootstrapping overhead: Launching a rollup is easy. Building an ecosystem around it is not. Each chain requires its own sequencer, bridge, indexer, wallets, and oracle infra — duplicated again and again.
User and value leakage: Every friction point — bridges, delays, wrapped assets —drives liquidity and users away from Ethereum toward other L1s or centralized platforms.
Why synchronous composability is the solution
Ethereum rollup ecosystems are only perpetuating walled gardens into walled forests. The OP Superchain cannot connect with Arbitrum Orbit or Base without a bridge making composability between rollup ecosystem difficult and burdensome for users and developers alike.
Compose is designed to address this!
The Core Features of Compose
Synchronicity: Real-time settlement across chains. Your multi-rollup action finalizes in the same block, delivering a seamless, one-click UX
Atomicity: All-or-nothing execution across rollups. If one leg fails, the entire transaction reverts — no risk of half-completed swaps or loans.
Speed: No more waiting on bridges or relayers. Transactions move instantly, unlocking fast DeFi and gaming experiences.
Composability: The holy grail of UX, apps interact seamlessly across rollups. Any token, any dApp, on any chain.
Compose compared to bridges
Message-passing bridges: These bridges don’t actually move tokens, they communicate across chains. A contract on chain A emits a message, which a relayer or committee then delivers to chain B. The assets remain locked on one side and minted/burned as representations on the other. Security depends on the trust model of the relayers. This is the dominant architecture for rollup bridges.
Liquidity/intent-based bridges: Instead of moving tokens directly, they rely on external liquidity providers. A user expresses an “intent” (e.g. swap 1 ETH on Arbitrum for 1 ETH on Optimism). The bridge’s LP fulfills it instantly from their own inventory, then later settles across chains asynchronously. This improves UX speed but introduces dependence on third-party liquidity and solvency.
Compose: Compose introduces synchronous composability through ZK aggregation & smart messaging. Through the Shared Publisher architecture, rollups coordinate transactions atomically using Ethereum’s validator set. That means cross-rollup swaps, flash loans, or arbitrage execute in one transaction — or not at all. No wrapped assets, no liquidity fragmentation, no trust in third-party relayers. Just Ethereum-grade security, extended across rollups
Bridge Type / Model | Atomicity | Synchronicity | Speed | Composability |
Message-Passing Bridges | No | No | Moderate | Moderate |
Liquidity / Intent-Based Bridges | No | No | High | Moderate |
Compose.Network (Shared Publisher) | Yes | Yes | Very high | Very high |
|---|
The Shared Publisher: Composability’s missing link
At the heart of Compose is the Shared Publisher (SP). It separates sequencing from publishing so that:
Each rollup retains sovereignty over its own sequencer and fee market.
Sequencers coordinate cross-rollup bundles using a two-phase commit protocol for guaranteed atomic execution and ZK proof aggregation for finality.
The Shared Publisher, based on Ethereum’s validator set, aggregates rollup blocks into superblocks and posts them to L1 via L1 validators.
This design restores synchronous composability without adding new trust assumptions, bridges, or central points of failure. It scales horizontally while staying aligned with Ethereum’s security model, all without sacrificing rollup sovereignty.
As a horizontal scaling and coordination layer that connects with both the rollups that opt into the network (aka. integrated rollups) and existing rollups (aka. included rollups) like Base, Optimism, and Arbitrum no heavy integration or adaption to infrastructure is needed to be supported by Compose.
What UX can look like in practice with Compose:
Borrow on Included Chain A: Uniswap, Base etc.
Do the work on Chain B (R1): Deposit, swap, liquidate, whatever the alpha is.
Repay on Chain A: All legs are committed (or none) in the same L1 block via the publisher’s 2-phase commit.
Multi-chain transactions can be done via multiple integrated chains together and 1 included chain at a time. The Shared-Publisher (SP) acts as a coordination layer between multiple rollups, facilitating cross-chain transactions and allowing rollups to capture interop fees.
Validators as blockchain composers
Ethereum validators are evolving. They’re no longer just block proposers — they’re becoming blockchain composers. In Compose, validators power the Shared Publisher, ensuring cross-rollup coordination is secured at Ethereum’s root of trust.
But this demands reliability, redundancy, and decentralization across validator infrastructure. Which is why Compose is being built with the best. More on this soon!
The final composition: What Ethereum can look like with Compose
Users: Ethereum feels whole again. One-click UX works across rollups, liquidity is unified, and every action inherits Ethereum’s validator-backed security. Innovative cross-chain actions become the norm.
Developers: No more rebuilding across different rollup ecosystems, your users don’t have to off-board to run to the new shiny thing. Built once, composed everywhere.
Validators: Validators evolve into multi-service providers. By using validators they can earn staking rewards and Shared Publisher rewards on top of that, while contributing to Ethereum’s decentralization and composability.
Rollups: Composability between all L2s. Everything is connected and works together. Liquidity and users are not fragmented anymore. No need to deploy your dApp in many rollups, Compose enables any user to reach your dApp from everywhere.
Ethereum: The network as a whole regains its network effects. Value flows back to ETH, validator incentives strengthen, and the rollup roadmap gains composability without compromising sovereignty.
A new era for Ethereum
The next chapter in Ethereum’s story isn’t about competing L1s or fragmented rollups. It’s about unity through synchronous composability.
And it’s powered by validators. Without being based, the Shared Publisher couldn’t be credibly-neutral, decentralized, or resilient enough to scale to meet the needs of all rollups. Compose can transform Ethereum’s validator set into the backbone of synchronous composability.
In the meantime, stay tuned for the Devnet release and more technical details on the website blog and X.
Compose Network is here to connect every corner of Ethereum - secured and powered by L1 validators.