Rollup Architecture

As mentioned in the What is Eco? section, the Eco Protocol involves two discrete systems working in concert:

• A Cross-Chain Transfer System, which provides developers with secure stablesend/swap pathways between any rollup settling on Ethereum (L2 or L3). This system should enable developers or their end users to opt into speed or trust tradeoffs which best fit their needs.

• A Dedicated Eco Rollup, natively integrated with the cross-chain transfer system, optimized for hyper-cheap and lighting-quick stablecoin transactions, with native functionality which makes it easy for app developers to integrate and provide more intuitive UX to end users. We want our rollup to be the default home for apps constructing the onchain payments stack or otherwise defaulting to stablecoins for their use case.

This section goes over the architecture for the Dedicated Eco Rollup. The rollup is not live in the current Alpha launch, but will become live during the Beta Launch of the Eco Protocol. Please see the Roadmap section for more details.

Eco Rollup

The Eco Rollup is an opinionated blockchain architecture with purpose built infrastructure for developers building global, crypto-abstracted payment experiences. At a high level, Eco is a Layer 3, EVM-compatible rollup that uses Celestia for data availability, and contains a payment-biased architecture that will be launched with support for cross-chain interactions and intents, and will be extended to provide virtual machine level optimizations for stablecoin transfers. Eco will include protocol bridges for many of the most globally prominent and geographically adopted blockchains, allowing users to seamlessly deposit funds into applications running on the chain.

High-Level System Architecture

Free Transactions for Partner Applications and Select Users

The use of a Layer 3 architecture with Celestia for Data Availability means that transaction costs are low enough for the sequencer to sponsor specific transactions. This pattern is employed on the Syndicate Frame Chain, which provides user specific API endpoints for free transactions. The API endpoint makes it possible to prevent abuse through rate limiting on specific accounts abusing or spamming the network. This architecture means that application developers can make business agreements with the Eco sequencer provider to provide free transactions to their users.

These forms of alternative monetization are much more preferably to the existing paradigm of having users pay extremely small fees (that add undue burden to users to get gas tokens) and that are negligible to sequencer providers and cause more harm to the adoption of networks than good.

Protocol Enshrined Bridges

The rollup will use “lock and mint” bridges to source stablecoin liquidity from all relevant chains that it and the transfer protocol supports. “Lock and Mint” bridges mean that stablecoins will be deposited on source chains, and minted on the Eco rollup using an "xAsset" style of representation. Architectures that commingle different assets from different chains into a single wrapped stablecoins must grapple with the systemic risk introduced by doing so. Providing an architecture that legibly displays the specific asset from the specific source chain allows applications to decide which stablecoins are prudential for their applications.

Eco will utilize Hyperlane to secure its cross chain lock and mint bridges, which will whitelist specific stablecoin assets for deposit onchain. These bridges will allow users to seamlessly deposit or withdraw funds from applications running on Eco, and provide application developers composable bridges into their applications.

At launch, these bridges will support simple deposits and withdrawals, and will also support post-bridge interactions. Support for post-bridge interactions will enable application developers to support smart contract interactions on other chains (like a payment or NFT mint on a specific chain) while consolidating balances on a single chain.

Eco stablecoin assets bridged from canonical chains will have a naming schema of ${chain}${asset}. For example, USDC canonically bridged from OP will have the convention of opUSDC and USDT bridged from Base will have the naming convention baseUSDT.

Enshrined Stablecoin AMM

Eco will employ an enshrined AMM to pair together representations of stablecoins from the various source chains. The pools will be optimized for efficient settlement between stablecoin pairs and provide a simple way for application developers to swap between assets on different source chains to support complex cross chain interactions or to support asset preferences.

Stablecoin liquidity concentration, plus cheap execution cost for swapping, will provide the ability for application developers to enable seamless experiences for p2p payments.

Beam intends to allow merchants to opt into expressing which stablecoin they would like to receive for payment. Whenever the merchant asks for payment, Beam would structure transactions from customer wallets to autoroute their funds through liquidity pools and into the desired stablecoin. This would allow an EU merchant to accept EURC while abstracting away this preference from their customers.

Native Stablecoin Transfers

Eco will enshrine select stablecoins as gas tokens to reduce the cost of stablecoin operations even further and to favor stablecoin activity over alternative activities on chain. To allow gasless transfers, the Eco rollup will ensure all native and bridged stablecoins support signature based transfer methods (like permit2 and others), to allow users to not have to worry about gas tokens for transfers.

Account Abstraction Infrastructure / RIP-7212 Support

A core focus of the Eco Protocol is extremely slick user experience. To that end, the Rollup will support Account Abstraction infrastructure from day one, and will incorporate any emerging Account Abstraction improvement proposals into the rollup. For example, Eco will support RIP-7212 to support passkeys in Apple and Android devices natively. This will allow signatures on the Eco chain using best in class UX, and using the Hyperlane post-bridge actions feature, allow for actions on other chains using those same signatures.

Cross-Chain Transfer System Integration

The combination of the rollup and the transfer system provide an promising direction for the protocol to provide the absolute cheapest intent fills possible. In this paradigm, users and fillers would be able to opt into the proof of intents and claiming of rewards on the Rollup

Submitting a typical storage proof on a rollup like Base or Optimism incurs a significant execution fee and massive data availability cost. Allowing fillers to claim and prove intent fulfillments on the Eco Rollup will dramatically improve the cost of proving intents and allow fillers to take advantage of the coming Storage Proof Precompile and cheap execution environment of the Eco Rollup.

This also provides fillers an extremely convenient place to manage their liquidity, as they can fill intents by bridging any stablecoin out of the rollup to fill intents on the chain that stablecoin lives through post bridge hooks. The on-chain native AMM means fillers can easily balance funds between rollups on one chain, making it possible to rebalance and manage all their liquidity on one chain.

Finally, this presents a great benefit for Users who consolidate cross-chain balances on the Rollup. These users can take advantage of extremely cheap transfers on all other supported chains using the Cross-Chain Transfer System, or can use post-bridge hooks to perform these actions themselves.

An L3 can acquire the state of the L2, the L1, and any L2s running on that L1 using the same methods described in the Technical Background section. At a high level, this is because Eco will expose it's settlement chain's block hash in the execution enviroment. Using this blockhash, it is possible to provide a "Russian Doll" proof that proves the L1 state using the L1Block oracle contract contained in the blockhash.