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Metalayer’s bridge aggregation system routes cross-chain transfers through multiple execution paths, including intent-based protocols with competitive solver markets. While not all bridge requests are intents, intent-based execution provides the fastest and most efficient routes for many cross-chain transfers.

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Intent-Based vs Direct Bridge Routes

When you make a bridge request via the Metalayer SDK, Widget, or API, the system may route your transaction through different types of providers: Intent-Based Routes (this page focuses on these):
  • Across Protocol: Independent intent-based protocol using UMA for verification and settlement
  • Relay Protocol: Independent intent-based protocol using direct rebalancing for settlement
  • Eco Solver (Caldera): Metalayer-Powered solver focused on ETH and native tokens
  • Eco Solver (Eco): Metalayer-Powered solver focused on stablecoin routes
Direct Bridge Routes:
  • Native Bridges: Direct integration with L2 canonical bridges (Arbitrum, Optimism, etc.)
  • Other Bridge Providers: Direct protocols without solver competition
All routes benefit from Metalayer’s aggregation, quote optimization, and unified developer experience, but only intent-based routes use the competitive solver model described below.

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How Intents Work

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Declarative Execution

Developers specify what they want to achieve (the intent) without needing to define how it should be executed across different chains. This abstraction reduces complexity and potential errors in cross-chain operations.

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Competitive Solver Model

Intent-based protocols use a competitive solver ecosystem where multiple entities compete to fulfill user intents:
  • Fast-Fill Networks: Solvers use their own capital to instantly deliver assets on destination chains
  • Competitive Fulfillment: Multiple solvers compete on speed, cost, and reliability
  • Risk Management: Solvers temporarily take on cross-chain settlement risk
  • Proof of Fulfillment: Solvers must provide cryptographic proof of completion via MetaProver

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Settlement Mechanisms

Different intent-based protocols use different settlement approaches:
  • Across Protocol: Uses UMA’s optimistic verification system
  • Relay Protocol: Uses direct rebalancing mechanisms
  • Eco Solver: Uses Metalayer’s intent system on supported networks, Hyperlane for all networks

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Intent Flow Example

User Intent: "I want 100 USDC on ApeChain, I have ETH on Arbitrum"

1. Intent Processing:
   - Parse user requirements
   - Identify source assets (ETH on Arbitrum)
   - Define destination requirements (100 USDC on ApeChain)

2. Quote Aggregation:
   - Query supported providers for optimal routes
   - See [Aggregated Bridges](/metalayer/resources/aggregated-bridges) for complete provider list

3. Route Selection:
   - Evaluate by speed, fees, and solver capacity constraints
   - Present optimal route to user (may be intent-based or native bridge)

4. Execution (Intent-based route):
   - User signs transaction, funds escrowed in Vault (Metalayer-Powered routes only)
   - Intent registered in IntentSource contract (Metalayer-Powered routes only)
   - Solver fulfills instantly on ApeChain using own capital

5. Settlement (Intent-based route):
   - External protocols (Across, Relay): Handle their own settlement mechanisms
   - Metalayer-Powered routes (Eco):
     - Solver's fulfillment logged in Inbox contract
     - MetaProver generates proof of fulfillment
     - Proof sent via Hyperlane to source chain
     - IntentSource marks intent as complete
     - Solver claims reimbursement from Vault

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Security Model

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Intent Verification

  • Cryptographic Commitments: Intents are cryptographically signed and immutable
  • Execution Guarantees: System ensures intents are fulfilled as specified
  • Proof of Fulfillment: Solvers must provide cryptographic proof of completion

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Solver Network Security

  • Capital Commitments: Solvers deploy their own liquidity and maintain inventory across chains
  • Route-Level Limits: Caldera enforces per-route maximums and cooldowns to cap exposure
  • Diverse Providers: Multiple external partners (Across, Relay, Eco) can service the same intent type
  • Operational Monitoring: Real-time tracking of fill latency, rebalancing health, and fulfillment accuracy
Additional mechanics such as solver slashing and shared staking pools are on the roadmap and will be announced separately.

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Integration

For developers building on Metalayer, bridge requests (including intents) are expressed via the Metalayer SDK. The SDK aggregates across multiple providers and may route through intent-based protocols or direct bridges: 
import { MetalayerClient, OrderStatus } from '@metalayer/sdk';

const client = MetalayerClient.init({
  apiKey: process.env.METALAYER_API_KEY!,
  environment: 'production',
});

// Discover supported routes dynamically
const { chains } = await client.getSupportedChains();

const quoteResponse = await client.quote({
  sourceChainId: 42161, // Arbitrum
  sourceTokenAddress: '0x0000000000000000000000000000000000000000', // ETH
  destinationChainId: 33139, // Apechain
  destinationTokenAddress: '0x0000000000000000000000000000000000000000', // ETH
  amount: BigInt('1000000000000000000'), // 1 ETH
  senderAddress: '0xYourWalletAddress',
});

const bestRoute = quoteResponse.quotes[0];
const submittedTxs: string[] = [];

for (const step of bestRoute.steps) {
  switch (step.action.case) {
    case 'transactionRequest':
      const txHash = await walletClient.sendTransaction(step.action.value);
      submittedTxs.push(txHash);
      break;
    case 'eip712Data':
      await walletClient.signTypedData(step.action.value);
      break;
  }
}

const { order } = await client.getOrder({
  sourceTransactionHash: submittedTxs[0],
  sourceChainId: 42161,
});

if (order.status === OrderStatus.FULFILLED) {
  console.log('Bridge order completed successfully');
}
The SDK abstracts quote aggregation, calldata assembly, and fulfillment tracking across both intent-based protocols and direct bridges, so you can focus on the user experience rather than managing multiple bridge integrations.

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Next Steps

Message Passing

Learn about the underlying messaging infrastructure

SDK Integration

Start building with intents