The Ethereum Interoperability Layer EIL is here! L2 fragmentation ends one-click cross-chain friction.

The Ethereum Foundation has proposed the Ethereum Interoperability Layer (EIL) solution, allowing all L2s to feel like a unified chain. Users only need to sign once to complete cross-chain transactions, without having to consider bridges, identify chain names, or worry about fragmented balances. EIL is built on the principles of ERC-4337 account abstraction and “trustless declaration,” enabling users to initiate and settle cross-L2 operations directly from their Wallets, without going through Relays or Solvers.

L2 Fragmentation Crisis: Multiple Ethereums Instead of One Ethereum

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L2 chains have significantly improved throughput and cost-effectiveness, with Ethereum achieving scalability through Rollup, providing ample block space and low transaction costs. However, they also introduce a new complexity for users and wallets. From the user's perspective, the result is a reduction in the number of Ethereums, replaced by multiple independent Ethereums. Users need to manage chains, not just conduct transactions.

Four Major Pain Points Faced by Users

Asset Location Difficulty: On which chain is my token? I need to switch between multiple Wallet interfaces to search.

Cross-chain transfer complexity: How to transfer tokens from Arbitrum → Base → Scroll → Linea? Each time it requires manual operation of the bridge.

Trust assumption increase: Do I need to trust third-party bridges or relays? Introducing new security risks.

High Integration Costs: Do my Wallet or dApp need to manually integrate each new chain? The burden on developers is heavy.

This will bring friction, cognitive burden, and often requires reliance on additional trust mechanisms—such as bridges, relays, and solvers—while also increasing the risk of censorship. The current challenge lies not only in throughput but also in how to provide a seamless user experience in a multi-chain environment. The current cross-L2 interoperability still resembles the centralized exchange (CEX) model, with bridge operators, relays, solvers, and opaque off-chain infrastructure.

In a sense, the Ethereum L2 ecosystem is facing the same dilemma as the early internet. Before HTTP, users could connect to a single server but could not seamlessly combine them into a single flow. HTTP unified the user experience, allowing browsers to easily access servers. The goal of the Ethereum Interoperability Layer (EIL) is to achieve the same for Ethereum's Rollups: to bring Ethereum into the “network era,” where wallets operate like browsers, enabling users to navigate freely between L2 layers without any friction.

EIL Vision: Multiple L2 One Ethereum Experience

What if all L2 layers felt like a unified Ethereum? No need to worry about bridge issues, no need to identify chain names, and no need to worry about dispersed balances or assets. This is the vision of the Ethereum Interoperability Layer (EIL): to make Ethereum feel like a chain again—while maintaining the trust minimization and decentralization foundations that we all care about.

Imagine a scenario like this: open your Wallet, select the assets and address, and then click “Send”. Your Wallet will automatically determine which chain it is on and how to deliver the assets in the background. You can mint NFTs, transfer tokens, trade assets—regardless of where the Rollup or dapp of you or your counterparty is deployed. New networks join the ecosystem, and your Wallet can work with them seamlessly—no need for custom integrations, no reliance on off-chain operators.

This is EIL. It focuses on a wallet-centric multi-chain user experience: the wallet becomes your universal gateway into the Ethereum ecosystem, and the network feels like a seamless whole experience rather than being pieced together by individual islands. EIL makes Ethereum's Rollup transactions feel like a single unified chain, allowing users to sign once to complete cross-chain transactions without introducing new trust assumptions.

From the user's actual experience, cross-chain transfers have become extremely simple. Alice's USDC is stored on the Arbitrum network, while Bob's USDC is stored on the Base network. With just a click, Alice's Wallet can transfer USDC to Bob's Base address. From Alice's perspective: “Send USDC to Bob”—she doesn't care which network the transfer happens on. Cross-chain minting is just as seamless; Alice holds ETH on Arbitrum and Scroll, and she wants to mint an NFT on Linea. Her Wallet will automatically merge the balances and transparently handle cross-chain gas fees and asset transfers, requiring just one click and a single signature.

Trustless design principles and technical architecture

EIL is built on the principles of ERC-4337 account abstraction and “trustless declaration.” While the consistency of user experience is important, it must not compromise Ethereum's core values: self-custody, censorship resistance, privacy, and verifiability. Users hold their assets and initiate transactions independently, with no intermediary able to block or delay transactions, without revealing their IP address or intentions to relayers or solvers, and any critical logic can be verified on-chain or in open-source wallet code.

The design of EIL follows the principle of trustlessness. It moves logic on-chain and integrates it into the user's Wallet, thereby eliminating reliance on intermediaries and opaque server logic. Users can transact directly across all chains; trustless liquidity providers supply funds but never interact directly with users or view their transaction history. Rather than saying “I trust the bridge operator to transfer my funds,” it's more accurate to say “my Wallet and contracts will operate according to verifiable rules.” The boundaries of trust remain weak.

This design philosophy is in line with the core innovation of Ethereum. The great innovation of Ethereum lies in replacing intermediaries with verifiable code. Before the emergence of Ethereum, cryptocurrencies relied on centralized exchanges (CEX), and the advent of Ethereum made decentralized exchanges (DEX) possible—no need to trust custodial entities, no counterparty risk, just verified smart contracts. DeFi has changed the world by providing a traditional financial alternative that does not require intermediaries. Trading across L2 layers should be as trustless as using a DEX.

EIL retains the core guarantees of Ethereum: self-custody, censorship resistance, decentralization, and verifiable on-chain execution. This brand-new account-based interoperability layer unifies Ethereum's decentralized L2 ecosystem under Ethereum's own security model. Users can initiate and settle cross-L2 operations directly from their Wallets without going through Relays or Solvers, fundamentally eliminating the reliance on third-party trust.

The Profound Impact on the Ecosystem and Call to Action

When interoperability shifts from integrating individual applications to wallet-level functionality, the entire ecosystem advances. Wallets and dApps natively support multiple chains, and the new version of Rollup automatically compatible accelerates adoption speed, allowing developers to focus on creating an excellent user experience rather than building cross-chain infrastructure. Users can experience the simplicity of Ethereum again: one wallet, one signature, multiple chains – a single experience. Most importantly, Ethereum's trust-minimized model remains intact without new intermediaries.

This brings us one step closer to our original promise: a global, open, seamless, and trustless world computer. Ethereum has achieved scalability, but what lags behind is a sense of unity. The Ethereum Interoperability Layer is the next step in realizing this unity—your wallet is your portal, and each Rollup feels like a native extension of Ethereum, rather than a separate island.

The Ethereum Foundation sincerely invites wallet teams, dApp developers, web designers, and broader ecosystem members to join this journey. Together, we can not only enable Ethereum to achieve scalability but also realize its seamless uniqueness. Let us reforge the unified chain of Ethereum.