{
  "code": 400,
  "type": "ZIP_STATE_MISMATCH",
  "message": "Unable to create calculation. address_zip_code 92037 not found in the address_province TN. Ensure zip is up to date and formed correctly."
}

try {
  const response = await fetch('https://api.numeralhq.com/tax/calculations', {
    method: 'POST',
    headers: {
      'Authorization': 'Bearer sk_test_xxx',
      'X-API-Version': '2026-01-01',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify(calculationData)
  });

  if (!response.ok) {
    const error = await response.json();

    switch (error.type) {
      case 'ZIP_STATE_MISMATCH':
        // Prompt user to verify their address
        break;
      case 'PRODUCT_NOT_FOUND':
        // Create the product first
        break;
      case 'CALCULATION_EXPIRED':
        // Request a new calculation
        break;
      default:
        console.error(`Error: ${error.message}`);
    }
  }
} catch (err) {
  // Handle network errors
}