Cross-Chain Messaging

​

Core Concepts

​

Chains

​

Cross-Chain Operations

• Writes: Send messages and execute functions across chains
• Reads: Query data from contracts on other chains

​

Message Components

• Destination Domain: The target blockchain network
• Recipient Address: The contract address that will receive the message
• Read Operations: Optional queries to execute on other chains
• Write Call Data: The function call to execute on the destination chain
• Finality Flag: Whether to wait for source chain finality before relay

​

Configurable Finality

​

Soft Finality (Default)

• ~10 second latency
• Validators confirm sequencer commitment to include transaction
• Optimal for most applications needing quick settlement
• Trust assumption: Validators honestly report sequencer feed data

​

Finalized Mode

• Requires batch submission to parent chain and finality on that chain
• Provides protection against sequencer reorgs
• Note: Optimistic rollups retain 7-day dispute window
• Same validator trust model as soft finality, but with additional reorg protection
• Recommended for high-value transfers or security-critical applications

​

System Architecture

​

Component Architecture

​

Message Flow

​

Gas Abstraction

​

Security Features

​

Message Verification

• Cryptographic Proofs: All messages verified through Hyperlane’s security model
• Independent Validators: Sovereign validator set for enhanced security
• Configurable Thresholds: Adjust security requirements per message type

​

Cross-Chain State Reads

• Real-Time Data: Query contract state from multiple chains simultaneously
• Atomic Operations: Read results are included in message delivery
• Consistency Guarantees: Reads are executed at a consistent block height

​

Settlement Components

​

Core Contracts

• MetalayerRouter: Main entry point for dispatching cross-chain messages
• Inbox Contract: Logs fulfillment actions on destination chains
• IntentSource: Registry for user intents and execution tracking on source chains
• MetaProver: Service that generates cryptographic proofs of fulfillment

​

Settlement Flow

1. Message Dispatch: Application calls MetalayerRouter to send cross-chain message
2. Event Emission: Router emits message event picked up by validator network
3. Cross-Chain Relay: Validators transport message to destination chain
4. Execution Logging: Action logged in destination’s Inbox contract
5. Proof Generation: MetaProver constructs proof of fulfillment message
6. Settlement Verification: Proof sent back to source chain for final settlement

​

Future Evolution

​

Integration Examples

​

Basic Message Sending

import {IMetalayerRouter, ReadOperation} from "@metalayer/contracts/interfaces/IMetalayerRouter.sol";
import {FinalityState} from "@metalayer/contracts/lib/MetalayerMessage.sol";

IMetalayerRouter router = IMetalayerRouter(0x09Ce71C24ee2098e351c0cF2dC6431b414d247f3); // Apechain router
address receiver = 0x1234567890123456789012345678901234567890;
ReadOperation[] memory reads;
bytes memory callData = abi.encodeWithSignature(
  "settle(bytes32,address,uint256)",
  intentId,
  receiver,
  amount
);

uint256 fee = router.quoteDispatch(
  33139, // destination domain
  receiver,
  reads,
  callData,
  FinalityState.INSTANT,
  500_000 // destination gas limit
);

router.dispatch{value: fee}(
  33139,
  receiver,
  reads,
  callData,
  FinalityState.INSTANT,
  500_000
);

​

Cross-Chain Reads

address recipientContract = 0x9876543210987654321098765432109876543210;
ReadOperation[] memory reads = new ReadOperation[](2);
reads[0] = ReadOperation({
  domain: 1,
  target: 0x64FF4Fa53F2ae3f4dD0B3ad5A2ff2b0D6901b21f,
  callData: abi.encodeWithSignature("latestAnswer()")
});
reads[1] = ReadOperation({
  domain: 42161,
  target: 0xc778417E063141139Fce010982780140Aa0cD5Ab,
  callData: abi.encodeWithSignature("getReserves()")
});

uint256 fee = router.quoteDispatch(
  33139,
  recipientContract,
  reads,
  abi.encodeWithSignature("settle(bytes)" , readContext),
  FinalityState.FINALIZED,
  600_000
);

router.dispatch{value: fee}(
  33139,
  address(recipientContract),
  reads,
  abi.encodeWithSignature("settle(bytes)", readContext),
  FinalityState.FINALIZED,
  600_000
);

Reminder: Router addresses and domain IDs are listed in /metalayer/resources/contract-deployments. Always quote the fee before dispatching so the router call includes the correct gas payment.

​

Next Steps