Crosschain Interoperability in Plain English

The multichain future is here, but it’s far from simple. Today’s web3 ecosystem consists of separate blockchains, each with its own rules, structure, and limitations. Because of this, moving between them is often slow and confusing.

Most blockchains were not built to communicate with each other. That means users often have to move assets manually, switch back and forth between wallets to use their assets, and learn unfamiliar tools just to use the apps they want.

Crosschain interoperability changes this. It connects blockchains behind the scenes, allowing them to share information and assets, and supporting apps that operate across multiple chains. The result is a smoother, faster, and more flexible experience for everyone.

In this article, we’ll break down what interoperability means in plain English, explain how it works behind the scenes, and explore why protocols like Across are helping to build a more connected web3.

In simple terms, crosschain interoperability refers to the ability of different blockchains to interact with each other. Instead of being isolated, they can communicate and coordinate with one another to create connections between blockchains. 

One way to think about it is that each blockchain is like its own country, with its own language, currency, and laws. Without a means of connecting them—like bridges, border crossings, or translators—crossing between these countries can be slow, expensive, and confusing.

In this analogy, interoperability serves as the infrastructure that connects these countries.

Interoperability makes it possible for blockchains to communicate with each other behind the scenes, allowing users to avoid extra steps such as swapping tokens, switching wallets, or learning the ins and outs of every new network. Everything just works faster and more smoothly.

Notably, this shift in how blockchains connect matters because web3 isn’t made up of just a few networks anymore. There are now dozens of active blockchains, especially in the Ethereum ecosystem. Some are Layer 2s (L2s) or even Layer 3s (L3s). These are built on top of Layer 1s to help them run more efficiently and handle more activity.

Together, L1s, L2s, and L3s make up a massive and growing network and industry. In this realm, the top five blockchains alone hold more than $100 billion in value, driving a great deal of interest and speculation toward the industry. But most people often end up using a single chain, because moving between them is hard, and most of them don't communicate with each other by default.

This is why interoperability is so important as web3 evolves. By opening the gates between networks, users can explore new decentralized applications (dApps), access unique decentralized finance (DeFi) opportunities, move their assets freely, and tap into the incredible liquidity held throughout the vast blockchain ecosystem, no matter where they started.

Crosschain interoperability is more than a technical upgrade. It changes how people actually use web3. Without it, even simple tasks can become slow, expensive, or frustrating.

Many popular dApps, such as Aave on Optimism or GMX on Arbitrum, are only compatible with specific chains. To use them, you often need to move assets between networks. That means dealing with bridges, swapping tokens, or switching wallets, with each step adding time, cost, and sometimes even risk.

Interoperability removes those roadblocks. By connecting blockchains in the background, it enables users to interact with applications regardless of the location of their assets. Processes that used to take five steps can now happen in one.

Interoperability also helps users get more value out of their crypto, improving what’s known as “capital efficiency.” When liquidity is spread throughout multiple chains, people often pay higher fees or miss out on better prices. Interoperable systems reduce that friction, making it easier to achieve the best outcome.

As adoption grows, these systems that improve the user experience are only becoming faster and more efficient. 

Across, for example, processes L2-to-L2 transfers in as little as 3 seconds, with an average cost of around $0.04 per transaction. As of 2025, Across has processed more than $20 billion in crosschain volume, providing proof that interoperability is no longer just an idea but a working system today.

Additionally, interoperability gives users more flexibility and protection. By spreading assets across chains, users can avoid the risks of being stuck on a single network during outages, congestion, or security issues. All together, interoperability makes web3 more open and flexible, so crypto enthusiasts can explore freely without getting stuck in one place.

While protocols like Across are well on their way to making crosschain communication simple and seamless, it took some major breakthroughs to get there.

In the early days, most bridges used a system called lock-and-mint. When you wanted to move assets from one chain to another, your tokens would be locked on the first chain, and a copy would be created on the second. When you want to bridge tokens back to your original blockchain, the copy is burned, and the original is unlocked. It works, but it's slow and requires trust in the system holding your locked assets. This system worked, but it came with serious risks. If the bridge had a bug or a security issue, you could lose your funds.

Some well-known examples of lock-and-mint include:

The next major development was message-passing bridges, which allowed blockchains to send more than just tokens. These bridges could also pass instructions or data between chains, unlocking more use cases. Also, The messages have to be verified, which adds time and complexity. It’s more flexible than lock-and-mint, but can still be slow, expensive, and hard to maintain.

Two well-known examples of this model are:

Today, we’re in the middle of another major shift: what’s now being called the intents Revolution. Instead of users needing to figure out every step of a crosschain transaction, they can simply say what they want to happen, and it gets done. For example: “Bridge 100 USDC and swap it for ETH on the other side.” The request is broadcast offchain, and solvers compete to fulfill it as efficiently as possible behind the scenes.

Across is leading the way here, using intents to power fast, affordable transfers between chains. Again, the protocol already delivers strong performance, like 3-second fill times and low costs, while keeping all the complexity hidden from the user.

Looking ahead, the next big step is standardization. Right now, each project has its own way of handling intents and crosschain communication, which makes everything harder to connect. But the whole ecosystem works better when systems speak the same language. That might work in the short term, but in the long run, it leads to confusion, bugs, and extra work for developers. As crosschain interoperability grows, it's becoming more important for apps and protocols to follow the same rules. That’s where ERC-7683 comes in.

ERC-7683 is a universal standard for crosschain intents, co-developed by Across and Uniswap Labs. It defines an open-source format that lets apps and tools communicate across chains using a shared language for intents. This removes the need for each project to build its own crosschain logic from scratch.

Every intent has two parts: an offchain message (the user’s request) and an onchain settlement (the action that completes it). ERC-7683 standardizes this process, enabling seamless interaction between apps that follow the standard.

Think of it like the USB of crosschain communication. Before USB, every device had its own plug. Now, one standard lets everything connect. ERC-7683 does the same for intents.

With over 70 protocols and projects already supporting it (including backing from Vitalik Buterin and Ethereum Foundation members), ERC-7683 is quickly becoming the foundation for a more unified Ethereum ecosystem. It makes life easier for developers and delivers smoother experiences for users, regardless of which chain they’re on.

Let’s walk through what actually happens when you submit an intent using a protocol like Across:

1. You submit an intent: You tell the system what you want to happen (e.g., Bridge .01 ETH from Ethereum to Polygon).

2. A relayer picks it up: Relayers are offchain actors that scan for open intents. They compete to fulfill your request as quickly and cost-efficiently as possible. The winning relayer will receive your request and move to fulfill it, and will then send 0.01 ETH to your wallet on Polygon, using their own funds to cover the transaction.

3. The system verifies success, and the relayer gets reimbursed: Across checks that the transaction went through correctly on the destination chain. If a transaction gets disputed, it is sent to UMA for final resolution. Once everything checks out, the solver is reimbursed on the origin chain along with a small financial reward.

For users, crosschain interoperability isn’t just about connecting blockchains. It’s about making things simpler, faster, and cheaper. Intents-based systems do exactly that.

Traditionally, bridging tokens and swapping them on another chain required several steps: connecting to a bridge, switching networks, using a swap service, and confirming multiple transactions. It was slow, expensive, and prone to error. Now, intents-based crosschain systems streamline all of this into a one-click experience. Users simply confirm the transaction, and solvers handle the bridging, swapping, and routing in the background, often in seconds.

These one-click crosschain features are already live in dApps like Uniswap and PancakeSwap, where users can swap assets between chains without leaving the interface or switching networks. It’s not just faster, it’s cheaper too. While traditional bridging might take minutes and cost several dollars in gas fees, intents-based solutions often settle in seconds for just cents.

For anyone using DeFi tools, swapping tokens, or moving assets between chains, intents-based crosschain interoperability delivers a smoother, more cost-efficient experience.

In 2025, interoperability will be much more than a buzzword. It’ll be something you feel. The friction of switching networks, connecting wallets, or figuring out how bridges work will fade away. You’ll simply act, and the blockchain will meet you where you are.

Crosschain actions will be embedded directly into dApps, powered by shared standards like ERC-7683. What once required multiple apps and approvals will become a single, intuitive step, no network switching required.

Behind the scenes, smarter infrastructure is evolving. New security models and coordination mechanisms are making crosschain settlement safer. Shared standards are reducing fragmentation. And as real-world assets become tokenized, interoperability will be the foundation for trading them seamlessly across chains.

Yes, challenges remain (security, scaling, governance) but the path forward is clearer than ever. Open standards like ERC-7683 and intent-based protocols like Across are already proving what’s possible: crosschain experiences that are simple, fast, and secure.

Ready to see it in action? Get started with Across.