Ethereum Interop Roadmap: How to Unlock the "Last Mile" for Mass Adoption?

Written by: imToken

In the Web3 world, the narrative has always been evergreen from “cross-chain” to interoperability.

Of course, many people may not strictly differentiate the connotations of the two. If summarized in one sentence, cross-chain focuses more on assets, primarily solving the “transportation” problem; while interoperability (Interop) covers multiple dimensions such as assets, states, and services, aiming to solve the “collaboration” problem.

In fact, as modular narratives increase the number and heterogeneity of L1/L2, users and liquidity are further dispersed, and interoperability has been recognized as a more ideal end state than cross-chain — users no longer perceive which chain they are on, but only submit their intent once, and the system automatically completes the operation in the most suitable execution environment.

With the recent announcement of a new UX roadmap by the Ethereum Foundation (EF), along with a series of engineering advancements surrounding withdrawal delays, messaging, and real-time proof, the puzzle of interoperability is being systematically pieced together.

1. What exactly is “Interop”?

In simple terms, “interoperability” is much more than just an “asset bridge”; it is a combination of a complete set of system-level capabilities.

It means that different chains can share state and proof, smart contracts can call each other's logic, users can obtain a unified interaction experience, and each execution environment maintains the same level of trustworthiness within security boundaries.

When these capabilities are met simultaneously, users can truly focus on the value activities themselves, without being troubled by network switching, repeated authorizations, or liquidity fragmentation. This actually echoes the ultimate goal of cross-chain engineering: to allow users to concentrate on the flow of value itself, rather than the barriers between chains (further reading “The Evolution of Cross-Chain Engineering: From 'Aggregation Bridges' to 'Atomic Interoperability', what future are we heading towards?”).

Especially after entering 2024, modular narratives will enter a period of full explosion, with more and more fragmented L1 and L2 emerging, making interoperability no longer just high-sounding talk at the protocol layer, but truly sinking into the user experience and underlying application logic.

Whether it is an intent-centered execution architecture, cross-chain aggregation, or new forms of applications like full-chain DEX, all are exploring the same goal: to ensure that users and liquidity are no longer limited to the Ethereum mainnet, without the need for frequent network switches, but can complete the exchange of on-chain assets, liquidity provision, and strategy operations in a unified interface and one-stop service.

In other words, the ultimate vision of interoperability lies in completely removing the blockchain from the user's view—allowing DApps and projects to return to a user-centered product paradigm, creating a low-threshold environment that is easy to engage with and offers an experience close to Web2, eliminating the final barriers for outside users to seamlessly enter the Web3 world.

After all, from a product perspective, the key to mainstream adoption is not to make everyone understand blockchain, but to enable them to use it without needing to understand it. It can be said that if Web3 is to reach billions of people, interoperability is the “last mile” of infrastructure.

On August 29, the Ethereum Foundation released “Protocol Update 003 — Improve UX,” which continues EF's three strategic directions after restructuring its R&D team this year: Scale L1 (mainnet expansion), Scale Blobs (data expansion), Improve UX (improving user experience).

The core theme of “Improve UX” is interoperability.

Source: Ethereum Foundation

2. From “Cross-Chain” to “Interoperability”: Signals Released by EF

This article emphasizes interoperability as the core, aiming for a seamless, secure, and permissionless Ethereum ecosystem experience. The main idea can be summarized in one sentence: asset cross-chain is just the first step; the cross-chain collaboration of data, state, and services is the real “interoperability.” In the future, Ethereum plans to make all Rollups and L2 “look like a single chain.”

Of course, EF also admits that although most of the infrastructure and technology are mature (or about to mature), there are still several key engineering implementation steps needed to truly deliver these solutions to users and allow them to naturally integrate into the daily experience of wallets and DApps.

Therefore, EF has divided the R&D work of “Improve UX / Interop” into three parallel main lines: Initialisation, Acceleration, and Finalisation.

The first step is “initialization”, which aims to become the starting point for interoperability, making Ethereum's cross-chain behavior lighter and more standardized.

Core work includes making intents lighter and more modular, while establishing universal standards to facilitate the pathways for cross-chain assets and operations, and providing interchangeable and composable universal interfaces for different execution layers.

The specific projects implemented include:

Open Intents Framework (OIF): A modular intent stack co-built by EF in collaboration with Across, Arbitrum, Hyperlane, LI.FI, OpenZeppelin, etc., supporting the free combination of different trust models and security assumptions.

Ethereum Interoperability Layer (EIL): Led by the ERC-4337 team, it constructs a permissionless, censorship-resistant cross-L2 transaction transmission layer, making multi-chain transactions as seamless as those on a single chain.

A new set of standards (ERC series): covering interoperable addresses (ERC-7828/7930), asset integration (ERC-7811), multi-call (ERC-5792), intent and generic message interface (ERC-7683/7786);

The goal is straightforward: to decouple “what the user wants to do” (declarative) from “how the system executes it” (procedural), and to enable wallets, bridges, and verification backends to cooperate under a unified semantics.

The second part is the “Acceleration” phase, which reduces latency and costs, making multi-chain more real-time.

Specifically focus on reducing time and costs around measurable indicators such as “signature count, inclusion time, rapid confirmation, finality, and L2 settlement”. The levers here include L1 rapid confirmation rules (bringing strong confirmation to the 15–30 second range), shortening L1 slot time (research and engineering groundwork to reduce from 12s to 6s), and shortening the L2 settlement/withdrawal window (downgrading the optimistic 7 days to 1–2 days, or introducing ZK proofs and a 2-of-3 rapid settlement mechanism). These measures are essentially laying the foundation for cross-domain message passing and a unified experience.

Ultimately, this step is also the “final confirmation,” which includes combining real-time SNARK proofs with faster L1 finality to explore second-level finality interoperability forms. In the long run, this will reshape the landscape of cross-domain issuance, bridging primitives, and cross-chain programmability.

Objectively speaking, in the context of Ethereum, Interop (interoperability) is no longer limited to the concept of “asset bridges,” but is a collective term for a whole set of system-level capabilities:

Cross-chain data communication - different L2s can share states or verification results;

Cross-chain logic execution - one contract can call the logic of another L2;

Cross-chain user experience - users only see one wallet and one transaction, rather than multiple chains;

Cross-chain security and consensus - maintaining equal security boundaries between different L2s through proof systems;

From this perspective, Interop can be understood as a universal language for future Ethereum ecosystem protocols, whose significance lies not only in transferring value but also in sharing logic.

3. How does Ethereum pave the way for “interoperability”?

It is worth noting that recently Vitalik also initiated a discussion on the Ethereum Magicians forum regarding shortening the Stage-1 (first stage) optimistic withdrawal time, advocating for reducing the withdrawal cycle from the traditional 7 days to 1–2 days, and proposing to gradually introduce faster settlement and confirmation mechanisms under the premise of controllable security.

This discussion is ostensibly related to the withdrawal experience of Rollups, but in fact, it is a direct response to one of the three major directions of “interoperability”—Acceleration.

Source: Ethereum Magicians

After all, the delay in withdrawals is not just a user experience issue of waiting too long, but a liquidity bottleneck in the entire multi-chain collaboration system:

For users, it determines the speed of fund transfers between different Rollups;

For intention protocols and bridge networks, it affects the capital efficiency of solutions;

For the Ethereum mainnet, it determines whether the ecosystem can maintain consistency and security during more frequent interactions.

Vitalik's perspective essentially opens the floodgates for this. In short, shortening withdrawal times not only improves the user experience of Rollups but also unlocks infrastructure upgrades for cross-domain messaging, liquidity, and rapid state transfers. This direction is completely aligned with the goals of the EF in the “Acceleration” mainline, which aims to shorten confirmation times, increase settlement speeds, and reduce the cost of funds in transit, ultimately making cross-chain communication real-time, trustworthy, and composable.

These efforts will correspond with the Devconnect event held in Argentina on November 17. According to the official agenda, Interop will be one of the key themes of this year's Devconnect, and the EF team will also reveal more details related to the EIL (Ethereum Interoperability Layer) at the conference.

Overall, all of this points in the same direction - Ethereum is completing its transition from “scaling” to “integration.”

Of course, this article, as the first of the Interop series, merely raises the fundamental question that interoperability is the ultimate goal of cross-chain narratives, and provides a preliminary glimpse into the current technical path from EF to Vitalik's real-time discussions, from standardized engineering layouts to the gradually shortening settlement cycles. We are witnessing another structural upgrade in the Ethereum ecosystem.

In the future, we will continue to understand from different perspectives why interoperability is not just a bridge, but also the underlying protocol that connects the future of Ethereum.

Please stay tuned.