Errors

{
  "error": {
    "type": "invalid_request",
    "code": "invalid_phone_format",
    "message": "Invalid phone number format. Use international format like +447446466847.",
    "doc_url": "https://docs.nixflex.com/reference/errors#invalid_phone_format",
    "details": {}
  }
}

async function callNixflex(path, options) {
  const res = await fetch(`https://api.nixflex.com${path}`, {
    ...options,
    headers: {
      'Authorization': `Bearer ${process.env.NIXFLEX_KEY_ID}:${process.env.NIXFLEX_KEY_SECRET}`,
      'Content-Type': 'application/json',
      ...options.headers,
    },
  });

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

    switch (error.code) {
      case 'rate_limit_exceeded':
        // Wait then retry
        await sleep(2000);
        return callNixflex(path, options);

      case 'twilio_invalid_credentials':
      case 'number_not_in_twilio':
        // Show user-facing error
        throw new Error(`Twilio setup issue: ${error.message}`);

      case 'agent_not_owned':
      case 'invalid_api_key':
        // Auth issue — log and alert
        await alertOps(error);
        throw new Error('Auth failed');

      default:
        throw new Error(`Nixflex error: ${error.message}`);
    }
  }

  return res.json();
}