get_x402_examples

{
  "found": true,
  "action": "search",
  "examples": [
    {
      "title": "Generate EIP-3009 Payment Header",
      "description": "Create a Base64-encoded signed payment header using EIP-3009",
      "category": "client",
      "language": "typescript",
      "use_case": "Generate gasless payment authorization from user wallet",
      "code": "import { Facilitator } from '@crypto.com/facilitator-client';\n...",
      "dependencies": ["@crypto.com/facilitator-client", "ethers"],
      "notes": [
        "Signer must have funds to authorize (but NOT to pay gas)",
        "Facilitator pays gas fees on behalf of user"
      ],
      "github_source": "https://github.com/cronos-labs/x402-examples"
    }
  ],
  "total_count": 1
}

result = use_mcp_tool(
    server_name="cato",
    tool_name="get_x402_examples",
    arguments={
        "action": "get-overview"
    }
)

result = use_mcp_tool(
    server_name="cato",
    tool_name="get_x402_examples",
    arguments={
        "action": "search",
        "query": "payment header"
    }
)

result = use_mcp_tool(
    server_name="cato",
    tool_name="get_x402_examples",
    arguments={
        "action": "list",
        "category": "client",
        "language": "typescript"
    }
)

result = use_mcp_tool(
    server_name="cato",
    tool_name="get_x402_examples",
    arguments={
        "action": "list-all"
    }
)

import { Facilitator } from '@crypto.com/facilitator-client';
import { ethers } from 'ethers';

// 1. Initialize facilitator client
const facilitator = new Facilitator({
  network: 'cronos',
  apiUrl: 'https://facilitator.crypto.com'
});

// 2. Get payment requirements
const requirements = await facilitator.getPaymentRequirements({
  amount: '10.00',
  currency: 'USDC'
});

// 3. User signs payment with their wallet
const signer = new ethers.Wallet(privateKey);
const paymentHeader = await facilitator.generatePaymentHeader({
  signer,
  amount: requirements.amount,
  recipient: requirements.recipient,
  nonce: requirements.nonce
});

// 4. Make API request with payment
const response = await fetch('https://api.example.com/resource', {
  headers: {
    'X-Payment': paymentHeader
  }
});

import { FacilitatorServer } from '@crypto.com/facilitator-server';

const facilitator = new FacilitatorServer({
  network: 'cronos',
  merchantAddress: '0x...'
});

// Express middleware
app.use('/api/paid', async (req, res, next) => {
  const paymentHeader = req.headers['x-payment'];
  
  if (!paymentHeader) {
    return res.status(402).json({
      error: 'Payment required',
      payment_address: facilitator.getPaymentAddress(),
      amount: '10.00',
      currency: 'USDC'
    });
  }
  
  try {
    // Verify payment (no blockchain call, signature check only)
    const payment = await facilitator.verifyPayment(paymentHeader);
    
    // Settle payment on-chain
    const settlement = await facilitator.settlePayment(payment);
    
    // Payment confirmed, proceed
    req.payment = payment;
    next();
  } catch (error) {
    return res.status(402).json({
      error: 'Invalid payment',
      details: error.message
    });
  }
});

// Signature components
{
  from: '0x...',        // Payer address
  to: '0x...',          // Recipient address
  value: '1000000',     // Amount in token units
  validAfter: 0,        // Validity start time
  validBefore: MAX,     // Validity end time
  nonce: '0x...',       // Unique nonce
  v, r, s               // Signature components
}

# Install dependencies
npm install @crypto.com/facilitator-client @crypto.com/facilitator-server ethers

# Set environment variables
export FACILITATOR_API_URL="https://facilitator.crypto.com"
export MERCHANT_ADDRESS="0x..."
export NETWORK="cronos"