Bringing Interoperability to Arbitrum and Ethereum

Blockchain applications today provide a robust foundation for an onchain economy. It has never been easier for a developer to launch an application or chain while benefiting from Ethereum’s security and composability. But as adoption grows, so do its challenges.

Today, developers and users live in a fragmented blockchain landscape. Applications operate on isolated networks, limiting the ability to interact and transact seamlessly. The dream of a decentralized, global supercomputer is within reach, but only if these networks can operate in harmony. Vitalik’s blog post on scaling highlights this challenge as well, among other emerging focus areas for Ethereum L1. Solving this challenge requires not just innovation but also a commitment to openness and collaboration.

We at Offchain Labs believe that Arbitrum can and will lead the way, and developers will have access to a suite of interoperability solutions in two distinct phases:

1. Intent-Based Interoperability: Targeting the end of Q1, Arbitrum chains will have access to crosschain token transfers and swaps in less than three seconds.
2. Crosschain Operations: Targeting the end of Q3 and pending approval from the Arbitrum DAO, we will enable crosschain operations in a fast, cheap, and trustless manner.

These developments are just a few of several foundational improvements that will unify the Arbitrum ecosystem. By establishing seamless connectivity and liquidity sharing, users and developers will experience Arbitrum chains as a unified whole — a platform where true interoperability is achieved without compromising on security, UX, and the freedom to build anything you want.

While these innovations will elevate the Arbitrum ecosystem, the impact extends far beyond a single network. By making these developments available across all EVM-compatible chains. Offchain Labs is doing more than just improving Arbitrum — we’re weaving a seamless fabric of connectivity throughout the entire Ethereum landscape. This universal approach to interoperability marks a significant step toward a truly unified blockchain ecosystem.

Arbitrum Interoperability

Offchain Labs, the initial builders behind the technology used by Arbitrum, will work closely with the Ethereum Foundation, interoperability protocols, and leading L2s to align with industry standards, research improvements and ensure the broad adoption of these tools and protocols. While interoperability standards are important, we recognize that true interoperability will only come through actual selection and implementation of standards, turning ideas into reality.

Offchain Labs believes that it is crucial for interoperability to maintain several key properties:

1. Trustless: Crosschain communication should not introduce any new trust assumptions, or it risks undermining the core value proposition of blockchains today.
2. Cheap: Crosschain communication should not result in high fees that restrict accessibility.
3. Fast: Crosschain communication should occur much faster than L1 finality to help ensure practical functionality.
4. Accessible: Interoperability should be a feature available to everybody. Developers should have a clear path toward enabling crosschain communication, with no vendor lock-in, politics, or boundaries.

This means Arbitrum’s interoperability modules would provide functionality allowing crosschain communication and chain abstraction without cascading security risks or unspoken tradeoffs.

A Universal Intent Engine

Supporting the vision of a unified Ethereum, at the heart of Arbitrum’s interoperability vision is a universal intents engine. This engine will power crosschain swaps and transfers for all Arbitrum chains and EVM-based chains in less than three seconds, eventually allowing users to initiate complex actions with a single wallet prompt. The components outlined below are just the first step we are taking toward the vision outlined above. As we work to improve on the most critical properties for cross-chain operations — being fast, cheap, and trustless — the engine’s core components will change.

Intents are a rapidly growing connective layer well-suited for the multi-chain world. By allowing users to express crosschain intentions for their assets, solvers can compete to find the most cost and time-efficient path to the desired state. Users and apps get their assets fast while handing off the complexities of routing and chain management. Many different teams have laid the groundwork to make intents possible today.

The technology layer that powers intents is still nascent, and we plan to deliver upgrades on the protocol and application layer to improve trust, cost, and UX. Our initial intents engine consists of four components:

• Message Standard: All Arbitrum chains will be able to adopt a standardized message format for intents. Several standards show promise, including ERC-7683, 7786, and 7841. Note that these are not mutually exclusive and the combination of these standards can offer a powerful experience. Standardizing the message layer will reduce friction for solvers and intent solutions.
• Broadcast Standard: All Arbitrum chains will have standard contracts that ensure trustless communication, guaranteeing a secure message-passing connection between Arbitrum chains and the broader EVM ecosystem.
• Fast Settlement: Arbitrum chains will have access to various fast settlement solutions, including the already live Fast Withdrawals, third party fast bridges, and an upcoming native ZK integration. A shorter settlement time lowers the capital requirements for solvers and fast bridges to rebalance funds, meaning savings can be passed on as reduced user fees.
• Intent Dissemination Feed: Arbitrum chains and applications will have access to a universal feed to publish users’ intents. Initially, this component will depend on third parties, but Offchain Labs is exploring trustless solutions that seamlessly integrate with all available setups. This will allow users, developers, and solvers to have a frictionless experience in crosschain transfers and swaps.

Wen Interop?

Arbitrum’s Universal Intents Engine will launch in Q1 on an initial set of chains, making seamless cross-chain asset transfer a reality. This rollout will expand to encompass all chains and key applications on Arbitrum One, enabling secure, fast, and efficient intent execution ecosystem-wide. Offchain Labs is collaborating with other L2s and interoperability protocols in an EF working group to develop smart contracts that comply with ERC-7683.

To ensure a smooth expansion to new chains, The Arbitrum Foundation has confirmed that it will run a Solver Loan Program (SLP). The SLP will provide the capital to solvers willing to support intents across the Arbitrum ecosystem. The SLP will begin by bootstrapping ETH and USDC routes between chains, with plans to expand to additional tokens later in the year. Through this program, Arbitrum chains can also loan their own funds to establish routes for their custom gas and governance tokens.

On Our Radar

• Fast Settlement Solutions: Expanding on the live Fast Withdrawals feature, additional solutions, including a native ZK integration and support for 3rd-party pre-confirmation products, are being developed to accelerate settlement, pre-confirmation and optionality for chains.
• Developer Tooling: Expansion of the intent design space, including the enablement of complex interactions beyond simple transfers and swaps.
• Crosschain Standards: Establishing compatibility with widely accepted EVM standards, including ERC-7683, ERC-7785 and ERC-7828, to help ensure seamless interoperability across chains.
• Refining the UX: Exploring EIP-7702 and account abstraction to offer single-signature crosschain transactions.

By combining immediate advancements with long-term innovation, Arbitrum is delivering a cohesive and forward-looking ecosystem for users and developers alike. Offchain Labs is committed to continuously refining the intents stack — in tandem with many ecosystem partners — so that fast, trustless, cheap interoperability is available to all.

The Road Ahead

Through the Universal Intent Engine, the Arbitrum ecosystem will have access to crosschain token transfers and swaps in less than three seconds, but such improvements can’t stop there. Offchain Labs is committed to making crosschain operations better. Developers should expect to hear more about these plans soon.

Through these primitives, developers will have access to a comprehensive interoperability suite, enabling them to build applications that interact across chains without compromising security, decentralization, or speed. Users stand to benefit the most, where any action will be just one wallet prompt away. Upon completion and DAO approval of the interoperability suite, a user will gain access to any chain(s) of their choice, regardless of where their assets are.

Users will have access to any EVM chain or application on Arbitrum.

A unified Ethereum would not be possible without the contributions of others, including L2s, the EF, Espresso, Uniswap, Across, LayerZero, Chainlink, Polymer Labs, Open Zeppelin, Caldera, Reservoir, Li.Fi, Everclear, and many more. If you are building interoperability solutions or standards, we invite you to join us in shaping the next iteration of both Arbitrum and Ethereum. Together, we can make a trustless, decentralized future a reality.

If you are in the Arbitrum ecosystem and want to enable interoperability today, please refer to this document for more technical details.