Getting Started

// Select a gas fee option from the quote response
const selectedGasFeeOption = gasFeeOptions.feeOptions[0]; // Choose based on user preference

// Constants for the flow
const INTENT_ENTRYPOINT_ADDRESS = '0x9470d883bac170116d397db3da71b2e57d567583'; // Trails Intent Entrypoint (same on all chains)
const deadline = Math.floor(Date.now() / 1000) + 3600; // 1 hour from now

// 1. Get user nonce from Intent Entrypoint contract
const userNonce = await publicClient.readContract({
  address: INTENT_ENTRYPOINT_ADDRESS,
  abi: parseAbi([
    'function nonces(address user) view returns (uint256)'
  ]),
  functionName: 'nonces',
  args: [intent.ownerAddress]
});

// 2. Check if approval is needed for the deposit token
const tokenAddress = intent.depositTransaction.tokenAddress;
const currentAllowance = await publicClient.readContract({
  address: tokenAddress,
  abi: erc20Abi,
  functionName: 'allowance',
  args: [intent.ownerAddress, INTENT_ENTRYPOINT_ADDRESS]
});

const needsApproval = currentAllowance < BigInt(intent.depositTransaction.amount);

// 3. If approval needed, get permit signature for the deposit token
let permitSignature;
let permitDeadline;
let permitAmount;

if (needsApproval) {
  // Read token metadata for permit signature
  const tokenNonce = await publicClient.readContract({
    address: tokenAddress,
    abi: parseAbi([
      'function nonces(address owner) view returns (uint256)'
    ]),
    functionName: 'nonces',
    args: [intent.ownerAddress]
  });

  const tokenName = await publicClient.readContract({
    address: tokenAddress,
    abi: parseAbi([
      'function name() view returns (string)'
    ]),
    functionName: 'name'
  });

  permitDeadline = deadline;
  permitAmount = '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff'; // maxUint256 for infinite approval

  permitSignature = await walletClient.signTypedData({
    domain: {
      name: tokenName,
      version: '1',
      chainId: intent.originChainId,
      verifyingContract: tokenAddress
    },
    types: {
      Permit: [
        { name: 'owner', type: 'address' },
        { name: 'spender', type: 'address' },
        { name: 'value', type: 'uint256' },
        { name: 'nonce', type: 'uint256' },
        { name: 'deadline', type: 'uint256' }
      ]
    },
    primaryType: 'Permit',
    message: {
      owner: intent.ownerAddress,
      spender: INTENT_ENTRYPOINT_ADDRESS,
      value: BigInt(permitAmount),
      nonce: tokenNonce,
      deadline: BigInt(permitDeadline)
    }
  });
}

// 4. Sign the intent signature (ERC712) with fee payment authorization
const intentAddress = intent.depositTransaction.toAddress;
const intentSignature = await walletClient.signTypedData({
  domain: {
    name: 'TrailsIntentEntrypoint',
    version: '1',
    chainId: intent.originChainId,
    verifyingContract: INTENT_ENTRYPOINT_ADDRESS
  },
  types: {
    TrailsIntent: [
      { name: 'user', type: 'address' },
      { name: 'token', type: 'address' },
      { name: 'amount', type: 'uint256' },
      { name: 'intentAddress', type: 'address' },
      { name: 'deadline', type: 'uint256' },
      { name: 'chainId', type: 'uint256' },
      { name: 'nonce', type: 'uint256' },
      { name: 'feeAmount', type: 'uint256' },
      { name: 'feeCollector', type: 'address' }
    ]
  },
  primaryType: 'TrailsIntent',
  message: {
    user: intent.ownerAddress,
    token: tokenAddress,
    amount: intent.depositTransaction.amount,
    intentAddress: intentAddress,
    deadline: BigInt(deadline),
    chainId: BigInt(intent.originChainId),
    nonce: userNonce,
    feeAmount: BigInt(selectedGasFeeOption.amount),
    feeCollector: selectedGasFeeOption.feeCollectorAddress
  }
});

// 5. Execute with signatures
const executeResponse = await fetch('https://trails-api.sequence.app/rpc/Trails/ExecuteIntent', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-Access-Key': 'YOUR_ACCESS_KEY'
  },
  body: JSON.stringify({
    intentId,
    depositSignature: {
      intentSignature,                      // ERC712 intent signature
      permitSignature,                      // ERC2612 permit signature (optional if already approved)
      permitDeadline,                       // Permit expiration timestamp (optional)
      permitAmount,                         // Permit amount - typically maxUint256 (optional)
      selectedGasFeeOption,                 // Fee option with: amount, tokenAddress, feeCollectorAddress
      userNonce: Number(userNonce),         // User's current nonce from Intent Entrypoint
      deadline                              // Intent expiration timestamp
    }
  })
});

const { intentStatus } = await executeResponse.json();
console.log('Execution started:', intentStatus);

{
  "intentId": "0xc467d1ebb4c6aab9efd3485d2627e51fb8ce1f662808eccf1222f364a1aa2d01",
  "depositSignature": {
    "intentSignature": "0xe3e5a87b8c1a9f882f6b251ea551dc1703ce617a0308418...",
    "selectedGasFeeOption": {
      "tokenAddress": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
      "tokenSymbol": "USDC",
      "tokenDecimals": 6,
      "amount": "7845",
      "amountUsd": 0.007843596906252802,
      "feeCollectorAddress": "0x76008498f26789dd8b691bebe24c889a3dd1a2fc"
    },
    "userNonce": 1,
    "deadline": 1762424131
  }
}