How to Design a Protocol-Agnostic Integration Layer

A protocol-agnostic integration layer is an abstraction that sits between your application and the underlying blockchain protocols. Its primary goal is to standardize interactions, allowing developers to write code once and deploy it across different networks like Ethereum, Solana, or Cosmos. This is achieved by defining a common interface for core operations—such as reading state, sending transactions, and listening to events—while delegating the protocol-specific logic to modular adapters. This design decouples your application's business logic from the intricacies of any single chain, future-proofing it against ecosystem shifts and reducing integration complexity.

The foundation of this design is a well-defined abstract interface. This interface declares the essential functions your application needs, such as getBalance(address), sendTransaction(tx), or subscribeToEvent(eventName). Crucially, it contains no implementation details. For Ethereum Virtual Machine (EVM) chains, this might map to JSON-RPC calls via libraries like ethers.js or viem. For Solana, it would use the @solana/web3.js library. By coding against this interface, your application remains clean and portable. The concrete implementation is provided by adapter classes (e.g., EthereumAdapter, SolanaAdapter) that conform to this interface, translating the generic calls into chain-specific actions.

Implementing the adapter pattern requires handling the key differences between protocols. These include variations in transaction formats (EIP-1559 vs. versioned transactions), account models (Externally Owned Accounts vs. Program Derived Addresses), and consensus finality. A robust adapter must normalize these differences. For example, a signAndSendTransaction method in your abstract interface would be implemented by an EVM adapter crafting and signing an EIP-1559 transaction, while a Solana adapter would create a versioned transaction and request a signature from a wallet like Phantom. Error handling and gas/ fee estimation must also be abstracted to provide a consistent developer experience.

Beyond basic read/write operations, a production-ready layer needs state and connection management. This involves managing multiple simultaneous provider connections, handling chain reorgs, and providing real-time updates via subscriptions or polling. Using an event-driven architecture can help here. Furthermore, integrating a type-safe SDK generated from your core interface (using tools like TypeScript) ensures that developers using your layer get autocompletion and compile-time checks, drastically reducing errors. Popular frameworks in the space, such as Wagmi for EVM chains, exemplify this approach by providing React hooks that abstract away the RPC provider details.

Finally, consider extensibility and discovery. A good design allows new protocol adapters to be added without modifying the core application logic. This can be facilitated by a registry pattern or dependency injection. Also, incorporate a discovery mechanism so the application can dynamically learn about supported chains, their capabilities (e.g., does this chain support smart contracts?), and native asset information. By following these principles—abstract interfaces, the adapter pattern, normalized operations, and dynamic discovery—you build a flexible foundation that can integrate with today's protocols and adapt to the innovations of tomorrow.

A protocol-agnostic integration layer acts as an abstraction between your application's core logic and the underlying blockchains it supports. Its primary goal is to standardize interactions—like reading state, sending transactions, and listening to events—across different execution environments such as Ethereum, Solana, or Cosmos. The core dependency is a well-defined interface or adapter pattern. You define a common set of functions (e.g., getBalance, sendTransaction, subscribeToEvent) that each protocol-specific driver must implement. Popular libraries like ethers.js for EVM chains or @solana/web3.js for Solana become your building blocks, wrapped within these adapters.

Your architecture must handle fundamental blockchain disparities. Key considerations include: account models (EOA vs. program-derived), transaction formats (EIP-1559 vs. versioned transactions), consensus finality (probabilistic vs. deterministic), and fee markets. For instance, batching ten token transfers on Ethereum might use a multicall contract, while on Solana you'd compose an instruction array. A dependency like viem offers superior type safety and abstraction for EVM chains, making it a strong candidate for that side of your adapter layer. You'll also need a system for managing chain metadata—RPC endpoints, chain IDs, native currency details, and block explorers—often stored in a structured format like the Chainlist standard.

State management and error handling are critical dependencies. You must design for asynchronous operations and partial failures where one chain succeeds and another fails. Implementing a retry logic pattern with exponential backoff for RPC calls is essential. Furthermore, your layer should normalize error messages from different providers into a unified error taxonomy. For development, a multi-chain local testing environment is a prerequisite. Tools like Foundry's Anvil, Hardhat, and Solana's local validator allow you to test integrations without relying on live networks. This setup is crucial for verifying that your agnostic logic works correctly across simulated environments before deployment.

The primary goal of a protocol-agnostic layer is to abstract away the underlying complexities of different blockchains. Instead of writing custom integration code for Ethereum, Solana, and Cosmos, your application interacts with a unified interface. This is achieved through a core abstraction layer that defines standard methods for common operations like querying state, sending transactions, and listening for events. Popular frameworks like the Chain Abstraction Layer (CAL) concept or the EVM's Remote Procedure Call (RPC) specification serve as foundational models for this approach.

Core Component: The Adapter Pattern

At the heart of the system are protocol-specific adapters. Each adapter translates the generic calls from your abstraction layer into the native API calls of a specific blockchain. For example, an Ethereum adapter would implement a sendTransaction method using eth_sendRawTransaction via JSON-RPC, while a Solana adapter would use sendTransaction via its RPC methods. These adapters must handle chain-specific nuances like gas estimation, fee markets, and transaction serialization formats, insulating the core application logic from these details.

A robust integration layer requires a dynamic registry to manage these adapters. This component is responsible for discovering, registering, and versioning adapters for different networks. It allows the system to support new chains by simply adding a new adapter module, without requiring changes to the core application code. The registry often pairs with a configuration service that provides chain metadata, such as RPC endpoints, chain IDs, native token symbols, and block explorer URLs, enabling dynamic connectivity.

For state queries and transaction submission, you need a unified provider interface. This interface defines all necessary methods, such as getBalance, getBlockNumber, estimateGas, and getLogs. Here's a simplified TypeScript example of what this interface might look like:

typescriptCopy
interface BlockchainProvider {
  getBalance(address: string): Promise<bigint>;
  sendTransaction(tx: UnifiedTransaction): Promise<string>;
  getChainId(): Promise<number>;
}

Each concrete adapter (e.g., EthereumAdapter, PolygonAdapter) implements this interface, ensuring consistent behavior across protocols.

Error handling and retry logic must be built into the architecture. Different networks have distinct failure modes: an Ethereum transaction might fail due to insufficient gas, while a Solana transaction could fail from an invalid blockhash. Your integration layer should normalize these errors into a common set of exceptions and implement smart retry strategies, potentially with fallback RPC providers. Monitoring latency and success rates per chain and per provider is crucial for maintaining reliability and performance in a multi-chain environment.

Finally, consider the security and upgradeability of the integration layer. Adapters should be sandboxed or run with limited permissions, especially if handling private keys. The system should be designed to allow for seamless upgrades of individual adapters as blockchain protocols evolve. Using a modular, plugin-based architecture, as seen in projects like WalletConnect's Sign API or EIP-6963 for wallet discovery, ensures long-term maintainability and extensibility as the multi-chain landscape continues to expand.

A protocol-agnostic data model abstracts away the unique implementation details of individual blockchains—like Ethereum's Log events or Solana's Instruction formats—into a common, canonical representation. The goal is to create a single source of truth for on-chain activity that any downstream application can consume without writing custom parsers for each chain. This involves defining core entities such as Transaction, Block, Event, and Address with properties that are universally applicable, while using a flexible metadata field to store chain-specific data.

The schema must be extensible to accommodate new chains and data types. A practical approach is to use a base interface with required fields and a namespaced extension system. For example, a base ChainTransaction interface would have hash, blockNumber, and fromAddress. An Ethereum extension adds gasUsed and logsBloom, while a Solana extension includes slot and feePayer. This keeps the core model clean while preserving necessary details. Using a typed system like Protocol Buffers or JSON Schema ensures consistency and enables automatic client code generation.

Implementing the model requires a normalization layer, often called an indexer or adapter. This component listens to raw data from chain nodes, transforms it into the standardized format, and publishes it to a unified data stream or database. For instance, when processing an Ethereum ERC-20 Transfer event, the adapter would map the raw log topics and data to a canonical TokenTransfer event with fields amount, from, to, and tokenAddress. The key is that all adapters for different chains output the same TokenTransfer shape, making consumption trivial.

Real-world use cases demonstrate the model's power. A cross-chain analytics dashboard can query a single API for user activity instead of integrating with a dozen different RPC providers. A portfolio tracker ingests normalized transaction streams from Ethereum, Polygon, and Arbitrum to calculate a unified net worth. The model also future-proofs systems; adding support for a new Layer 2 like Base only requires writing one new adapter, not refactoring the entire application logic that depends on the data.

A protocol-agnostic integration layer acts as a bridge between your application's core logic and the diverse world of blockchains. Instead of writing unique code for each chain's RPC provider, transaction format, and smart contract ABI, you create a standard internal interface. Your application calls this interface, and a dedicated chain-specific adapter translates these calls into the precise format required by the target network. This abstraction is critical for building multi-chain applications, allowing you to support new chains by simply adding a new adapter without modifying your core business logic.

The first step in designing an adapter is to define a clean, chain-agnostic core interface. This interface should encapsulate the essential operations your application needs, such as readContract, sendTransaction, getBalance, and listenToEvents. For example, a readContract method would accept parameters like chainId, contractAddress, methodName, and args. The adapter's job is to take these generic parameters, connect to the correct chain's RPC endpoint (e.g., an Ethereum node via eth_call or a Solana RPC via getAccountInfo), format the request, and return a normalized response.

Each adapter must handle the unique intricacies of its target chain. For an EVM-compatible chain like Arbitrum or Polygon, this involves working with standard JSON-RPC, estimating gas, and signing EIP-1559 transactions. A Solana adapter, however, must construct VersionedTransaction objects, manage blockhash expiration, and submit transactions via sendTransaction. A well-designed adapter isolates these complexities. Consider using a configuration object for chain-specific constants: chainId, rpcUrls, nativeCurrency, blockExplorer, and any custom RPC methods.

Here is a simplified TypeScript example of an adapter interface and a partial Ethereum implementation:

typescriptCopy
interface ChainAdapter {
  chainId: number;
  readContract(params: ReadContractParams): Promise<any>;
  sendTransaction(params: TxParams): Promise<string>; // returns tx hash
}

class EthereumAdapter implements ChainAdapter {
  public chainId = 1;
  private provider = new ethers.JsonRpcProvider(RPC_URL);

  async readContract({ address, abi, functionName, args }: ReadContractParams) {
    const contract = new ethers.Contract(address, abi, this.provider);
    return await contract[functionName](...args);
  }
}

The adapter pattern allows your main application to call adapter.readContract() uniformly, regardless of the underlying chain.

Effective adapter architecture requires robust error handling and state management. Adapters should normalize errors from different chains into a common set of exceptions (e.g., RpcError, InsufficientFundsError, ContractRevertError). For stateful operations, implement a connection manager that instantiates and caches adapters based on chainId. Use the Factory Pattern to dynamically select the correct adapter: AdapterFactory.getAdapter(chainId). This setup is used by SDKs like viem and ethers.js for multi-chain support, where clients are configured for specific chains.

To maintain your integration layer, establish a testing suite that runs against testnets for each supported chain, verifying read and write operations. Keep adapters updated with chain upgrades, such as new precompiles or hard forks. By investing in this adapter architecture, you create a future-proof foundation. Adding support for a new chain like Monad or Berachain becomes a modular task—write one new adapter, implement the interface, and integrate it into your factory—unlocking new ecosystems without systemic rewrites.

A protocol-agnostic integration layer is an abstraction that sits between your application and multiple blockchain protocols. Its core purpose is to standardize interactions, allowing developers to write code once and deploy it across different networks like Ethereum, Solana, or Cosmos. The primary challenge is not just supporting different RPC calls, but abstracting away protocol-specific quirks in transaction formats, state queries, fee models, and error handling. A well-designed layer converts these heterogeneous interfaces into a single, consistent API for your application logic.

Start by defining a core set of standardized operations your application needs, such as sendTransaction, queryBalance, or listenToEvents. For each operation, create an abstract interface. Then, implement a concrete adapter for each target protocol. For example, an Ethereum adapter uses eth_sendRawTransaction, while a Solana adapter uses sendTransaction. The key is that both implement the same sendTransaction method signature internally, handling the conversion of a generic request object into the protocol-specific JSON-RPC call.

Error handling is where protocol-agnostic design is tested. Different chains return errors with varying structures, codes, and levels of detail. Your integration layer must normalize these errors into a common taxonomy. Create a central error handler that maps a Solana InstructionError or an Ethereum revert reason to a standard internal error type (e.g., InsufficientFunds, SimulationFailed, InvalidSignature). This allows your application to react to failures consistently, regardless of the underlying chain, using logic like if (error.type === 'InsufficientFunds') instead of parsing raw RPC responses.

Consider transaction lifecycle differences. On Ethereum, you wait for confirmations; on Solana, you check for confirmation status; and on Cosmos, you poll for transaction inclusion in a block. Your layer should provide a unified waitForConfirmation(txId) method that internally uses the correct polling mechanism and returns a standardized receipt. Similarly, fee estimation must be abstracted: convert Ethereum's gasPrice and gasLimit into a single maxFee object, while for Solana, compute prioritizationFee and account for computeUnits. The goal is to give the application developer a simple estimateFee(transaction) call.

Testing a protocol-agnostic layer requires a multi-chain simulation environment. Use local testnets or devnets (like Ganache, Localnet, or Anvil) for each protocol. Write integration tests that run your standardized operations against all adapters. Mocking RPC calls is insufficient; you must test the actual serialization, signing, and submission flow. A robust CI/CD pipeline should deploy and test against these ephemeral networks to catch regressions when new protocol upgrades (like an Ethereum hard fork or Solana runtime change) affect your adapters.

Finally, design for extensibility. New L2s and app-chains emerge constantly. Your architecture should make adding a new protocol as simple as implementing the defined adapter interfaces and adding its configuration. Use a factory pattern or dependency injection to instantiate the correct adapter based on a chainId or protocol identifier. By investing in this abstraction, you build a future-proof foundation that isolates your core business logic from the volatile and fragmented landscape of blockchain protocols.

To recap, a successful protocol-agnostic layer requires a clear separation of concerns. Your core application logic should be abstracted from the underlying blockchain's specifics. This is achieved by defining a common interface for key operations like sendTransaction, getBalance, and listenToEvents. Each protocol-specific adapter (e.g., for Ethereum, Solana, Cosmos) then implements this interface, translating generic calls into native RPC requests. This pattern, similar to the Adapter or Strategy design pattern in traditional software, is the architectural cornerstone.

Your next step is to implement a minimal viable adapter. Start with a single chain, like Ethereum, using ethers.js or viem. Create a class EVMAdapter that fulfills your core interface. Then, integrate a second chain with a different paradigm, such as Solana using @solana/web3.js. The challenge here is normalizing data structures; an Ethereum Log and a Solana Logs array have different shapes, but your application should receive a unified DecodedEvent object. Use TypeScript generics and union types to maintain type safety across these differences.

For production systems, focus on robust error handling and state management. Network requests can fail, chains can reorganize, and gas prices can spike. Your layer should expose standardized error types (e.g., RpcError, InsufficientFundsError, ChainNotSupportedError) and retry logic. Consider implementing a connection health check and failover mechanism to switch RPC providers if one becomes unresponsive. Tools like viem's public client and wallet client separation provide a good reference for managing different interaction modes.

Finally, evaluate higher-level frameworks that embody these principles. The Wallet Standard provides a common interface for wallet interactions across ecosystems. The Chain Agnostic Improvement Proposals (CAIPs) define standards for chain and asset identification (e.g., eip155:1 for Ethereum Mainnet). Integrating with or building upon these existing standards can accelerate development and ensure interoperability with the broader Web3 tooling ecosystem.

As you iterate, continuously test your abstraction. Add a new, unconventional chain (like Bitcoin via Lightning or a non-EVM L2) to your test suite. If integrating it requires changes to your core interface, your abstraction is leaking. The goal is that adding support for Chain X involves only writing a new adapter module, not refactoring the application business logic. This discipline is what ultimately future-proofs your application against the rapid evolution of the blockchain landscape.