Ethereum L2 Interoperability in 2025: What to Expect This Year?

Ethereum‘s (ETH) price performance in 2024 was a telling sign that all was not well with the world’s most valuable smart contract blockchain.

Critics of Ethereum’s rollup-centric roadmap have grown increasingly vocal, consistently pointing to the liquidity fragmentation and poor user experience caused by an excess of layer-two (L2) chains in the market today.

So, what does Ethereum have planned for 2025 to improve L2 interoperability? Let’s find out.

Table of Contents Table of Contents

1. Key Takeaways
2. What Is L2 Interoperability in Ethereum?
3. Key Developments in Ethereum L2 Interoperability in 2025
4. The Current State of Ethereum L2s
5. Why L2 Interoperability Matters
6. The Bottom Line
7. FAQs
8. References

Show Full Guide

Table of Contents

1. Key Takeaways
2. What Is L2 Interoperability in Ethereum?
3. Key Developments in Ethereum L2 Interoperability in 2025
Show Full Guide
4. The Current State of Ethereum L2s
5. Why L2 Interoperability Matters
6. The Bottom Line
7. FAQs
8. References

What Is L2 Interoperability in Ethereum?

L2 interoperability is the ability to seamlessly transfer assets and messages across different L2 chains. It refers to the composability of applications across various L2 chains on Ethereum.

For end users, interoperability solves L2 user experience issues related to switching chains, bridging assets, and managing multiple wallets when transacting across different L2 networks. For developers, it allows applications to interact with smart contracts on multiple chains, enabling the creation of solutions that leverage network effects across the Ethereum ecosystem.

Whether you are using Optimism Mainnet, Base or ZKSync Era, operating or developing on an L2 chain should feel like you are interacting with a unified blockchain ecosystem. That is the ultimate goal of L2 interoperability in Ethereum.

Key Developments in Ethereum L2 Interoperability in 2025

ERC-7683 Standardization

ERC-7683 is an Ethereum improvement proposal (EIP) that aims to standardize cross-chain interactions, such as token swaps, DeFi deposits, and governance votes.

The ERC-7683 cross-chain transaction standard was proposed by Uniswap Labs and Across in November 2024. At the time of writing, more than 30 blockchain networks and applications – including Optimism, Uniswap, Celestia, and Polygon – have committed to supporting the standard.

ERC-7683 introduces a standardized cross-chain intents system that can interoperate and share infrastructure between Ethereum mainnet and L2s. This system will be powered by network participants known as “fillers,” who will compete to fulfill cross-chain transactions in exchange for fees. A “prover” will be responsible for ensuring the proper fulfillment of transactions.

Across explained in a research post.

“Imagine swapping assets from Arbitrum to Polygon, buying NFTs on Optimism with ETH on Mainnet, or staking ETH from any L2 without ever using a bridge. ERC-7683 standardizes the processes in how these results are achieved, eliminating the barriers that make crosschain feel like crosschain.”

Interoperability Protocols: Polygon AggLayer & Optimism Superchain

Polygon’s AggLayer and Optimism’s Superchain are interoperability layers that provide L2 chains with a unified bridge to the Ethereum mainnet. While both solutions differ in architecture and features, their primary goal is to address the fragmentation problem within the Ethereum L2 ecosystem.

• AggLayer connects chains built with the Polygon Chain Development Kit (CDK), a developer toolkit for creating zero knowledge (ZK) L2s. It aggregates ZK proofs from all connected chains and enables near-instant cross-chain transactions.
• Superchain is a framework designed to unify L2 chains built using Optimism’s OP Stack. Member chains share a standard design, communication layer, open-source technology stack, security model, and governance structure.

At the time of writing, OP Mainnet, Base, World Chain, and Soneium were among the L2s who have joined the Superchain initiative. Meanwhile, Polygon zkEVM is the only protocol on Polygon’s AggLayer.

Welcome @inkonchain to the Superchain!@krakenfx is releasing @inkonchain, powered by the OP Stack.

Ink will provide a seamless onchain DeFi experience for the crypto-native and crypto-curious, contributing to the adoption of Ethereum. pic.twitter.com/JLkwuJEzk4

— Optimism.eth (@Optimism) October 24, 2024

Shared Sequencers & Proof Aggregation

Shared sequencers and proof aggregation technology are widely discussed as key solutions to Ethereum’s L2 interoperability challenges.

• Proof aggregation refers to bundling multiple chain states into a single zero-knowledge (ZK) proof before posting it to the Ethereum mainnet. This is achieved using a technique called recursion, where one proof can be composed of many others. Proof aggregation not only enhances synchronization across L2 chains but also reduces fees paid to the L1.
• A shared sequencer is a common sequencer node used by multiple L2 chains. For context, sequencers are nodes on L2 chains that batch transactions and settle them on the Ethereum mainnet. By adopting shared sequencers, rollup chains can share consensus, data availability, and settlement layers. Based rollups are the best example of L2 chains that use shared sequencers; they use the existing consensus layer on Ethereum to settle transactions on the L1.

The first ever based rollup—Taiko—is live!

the endgame is based pic.twitter.com/v3Aqa4w1od

— Justin.eth Drake (@drakefjustin) June 6, 2024

Confirmation Layers

Confirmation layers are solutions that provide chain operators with real-time information about the state of their own chain as well as other chains.

Such confirmations are important for inter-chain transactions, such as cross-chain mint-and-burn mechanisms, where nodes on each chain must have access to event confirmations on other chains in real-time.

A major purpose of our confirmation layer is to support interop protocols like CIRC, a simple yet powerful cross-chain messaging protocol we’re building that will enable synchronous composability across L2s.

Here’s @ellierdavidson, our head of R&D, explaining it at AggSummit. https://t.co/vXepUz8C39

— Espresso ☕️ (@EspressoSys) December 21, 2024

ERC-3770: Chain-Specific Addresses

ERC-3770 is an EIP that proposes introducing a new address standard for displaying chain-specific wallet and smart contract addresses. This proposal is a user experience-focused improvement that can be useful for cross-chain value transfer.

Wallet addresses are no longer deterministic. A wallet address on Chain A could coincidentally match a smart contract address on Chain B. Therefore, ERC-3770 seeks to solve this issue by implementing chain-specific addresses that automatically indicate their respective blockchain.

The Current State of Ethereum L2s

Ethereum is on a one-way path to scaling through its rollup-centric roadmap. So far, the adoption of rollups and L2 chains has successfully lowered gas fees and increased transaction speeds.

However, this progress has come at a cost.

A key critique of L2s is that they operate in isolation from each other, leading to fragmentation of liquidity across various chains. At the time of writing, over $42.75 billion in total value locked (TVL) was spread across 57 L2 chains, data on L2Beat showed. A user has to undergo the tedious process of bridging assets between L2 chains just to access their tokens on a specific network.

The proliferation of L2 chains has also resulted in a poor user experience. Users must switch between multiple networks, manage several wallets, and navigate a fragmented Ethereum L2 ecosystem These issues have presented Ethereum with a pressing issue that is adversely affecting its global adoption.

In a blog post on January 2025, Ethereum co-founder Vitalik Buterin called on the community to “stay the course” to scale Ethereum through L2s. Buterin said:

“One possible shortcut for scaling is to give up on L2s and do everything through L1 with a much higher gas limit. However, this approach compromises too much of the benefits of Ethereum’s current social structure, which has been so effective at getting the benefits of different forms of research, development and ecosystem-building culture at the same time. Hence, instead, we should stay the course, continue to scale primarily through L2s, but make sure that L2s actually fulfill the promise that they were meant to fulfill.”

Why L2 Interoperability Matters

There are a few reasons why L2 interoperability is important:

• Lower transaction fees: Direct interactions between L2s can significantly reduce cross-chain transaction costs.
• Secure cross-chain transactions: Interoperability solutions, such as direct mint-and-burn cross-chain smart contracts, will eliminate intermediary risks associated with traditional cross-chain bridges.
• Network effects: L2 interoperability will create a more cohesive Ethereum ecosystem, allowing applications to leverage deeper liquidity and stronger network effects.
• Cross-chain DeFi: Interoperability will allow DeFi applications to interact with smart contracts across multiple L2s, enabling seamless cross-rollup lending, staking, yield farming, and other DeFi services.
• Improved user experience: Users will be able to manage cross-chain assets within a single wallet and avoid the tedious bridging process when transacting across L2 chains.
• A unified Ethereum ecosystem: L2 interoperability should bring together the fragmented Ethereum L2 landscape.

The Bottom Line

2025 could be the year that Ethereum proves its doubters wrong.

For much of 2024, Ethereum quietly adapted and positioned itself to address the early challenges of its ambitious rollup-centric scaling roadmap. Now, by focusing on interoperability and user experience, the sleeping giant may finally be ready to awaken.

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