There are thousands of blockchains operating today, including Ethereum, Solana, Sui, Bitcoin, Cosmos, and many more. If you’re active in DeFi, chances are you’ve already interacted with more than one.
You might hold ETH on Ethereum, trade NFTs on Solana, and stake SUI on the Sui network. But what happens when you want to move tokens or data between them? It’s kinda like using different banks, except there’s no standard. Each blockchain is its own island, speaking its own language with other systems for communication.
Each blockchain was built differently. Different data formats, consensus methods, and smart contract engines. So, when one blockchain sees data from another, it’s like reading alien code. It just… doesn’t compute.

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What Is Blockchain Interoperability?

Blockchain interoperability (cross-chain) is the ability for two different blockchain systems to communicate, and that’s how it’s possible to transfer value between blockchains.In simple terms, it’s the tech that lets you send tokens, messages, or smart contract calls between completely different blockchains.
So, now you can swap your ETH for SOL or send a message from Sui to Ethereum without needing to jump through hoops or go through a centralised exchange.
Interoperability opens up a wide range of possibilities; everyone benefits, regardless of the chain they use most frequently. You’re not stuck on one chain anymore. You can hunt down better yields, lower fees, or specific apps across chains.
Think of them like an on-chain middleman that allows you to transfer tokens and NFTs to your favourite blockchain, even with different token standards.

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Types of Interoperability Systems

There are various forms and types of blockchain interoperability, each working differently to achieve the same outcome.

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Bridges

This is the most common form of interoperability. Bridges help you move tokens from one chain to another. How? They usually lock tokens on the source chain (the one you’re on) and mint a wrapped version on the destination chain (the one you’re going to).
  • Lock ETH on Ethereum → Mint wrapped ETH on Sui.
  • Burn wrapped ETH on Sui → Release the real ETH back on Ethereum.
Bridges are great for simple transfers like (ETH → SUI, SOL → AVAX, etc.)
Bridges come with risks, though. Most of them rely on external systems, so they are not fully decentralised.

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Interoperability Protocols

These protocols enable chains to communicate natively with each other, provided they adhere to the same rules. How? Each chain runs a light client of the other. This means they can verify each other’s state directly, without relying on third parties like oracles or relayers.
  • Chain A sends a packet → Chain B checks it using its built-in logic.
  • No wrapped tokens needed, just validated messages between chains.
Interoperability protocols are ideal for ecosystem-level communication, such as Cosmos chains communicating with each other using IBC or Polkadot parachains interacting via the Relay Chain. But they only work with compatible chains. You can’t use IBC to communicate directly with Ethereum or Solana (at least not yet).

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Cross-Chain Messaging Protocols

These protocols let smart contracts on one chain send messages to smart contracts on another chain. How? They package a message (such as “mint this NFT” or “trigger this action”) and then send it through a messaging layer. That message is picked up by relayers or oracles who deliver and validate it on the target chain.
  • Contract A on Ethereum → sends message → Contract B on Sui responds.
These protocols are ideal for dApps that require interoperability across multiple chains, such as lending on one chain and borrowing on another. They’re powerful, but still maturing. Message delivery and validation can be complex, and security is still evolving.

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Parallel MPC Interoperable Protocols

These are next-gen systems that enable fast, programmable communication across any chain, without relying on bridges or relayers. How? They use MPC (Multi-Party Computation) to generate secure signatures that are recognised across multiple chains. Everything is validated by a decentralised network of nodes that work together in real-time.
  • Transaction on Chain A → gets a sub-second signature → instantly valid on Chain B.
These protocols are ideal for DeFi protocols, asset managers, and developers building for speed and scale across multiple chains. It’s cutting-edge tech, though, with more moving parts, a wider attack surface, and fewer standards today. However, it’s gaining adoption rapidly. Here’s a summary of the types of interoperability porotocols:
TypeWhat It DoesBest ForHow It WorksRisks / LimitsExamples
BridgesMove tokens between chainsAsset transfersLock + release or burn + mintSecurity risks, often target of exploitsWormhole, Axelar, Circle CCTP, Orbiter
Interop ProtocolsNative communication between blockchainsEcosystem-wide connectivityShared rules + light clientsLimited to supported chainsCosmos (IBC), Polkadot (Relay Chain)
Cross-Chain Messaging ProtocolsSend messages or smart contract calls between chainsContract-to-contract calls, dAppsPayloads relayed + validated by oracles/guardiansComplex logic, still maturing in securityLayerZero, Hyperlane, Wormhole, Axelar
Parallel MPC Interop ProtocolsNative, programmable asset & data interop across any chainsScalable DeFi, protocol-native asset flowsSub-second MPC signatures, distributed keys, decentralized consensusNew tech, complex under the hood, wider attack surfaceIka Protocol
Now, you understand blockchain interoperability. Next, let’s overview Ika Protocol, one of the popular and interesting interoperability projects.