{
  "error": "human-readable message",
  "code": "ERROR_CODE"
}

const response = await fetch('/v1/peers', {
  method: 'POST',
  headers: { 'Authorization': `Bearer ${token}` },
  body: JSON.stringify({ address: '192.168.1.20:8080' })
});

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

  switch (error.code) {
    case 'ALREADY_EXISTS':
      console.log('Peer already in cluster');
      break;
    case 'NODE_LIMIT_EXCEEDED':
      console.log('Upgrade license for more nodes');
      break;
    case 'HANDSHAKE_FAILED':
      console.log('Check network connectivity');
      break;
    default:
      console.log(`Error: ${error.error}`);
  }
}

async function apiCall(url, options, retries = 3) {
  for (let i = 0; i < retries; i++) {
    const response = await fetch(url, options);

    if (response.ok) return response.json();

    if (response.status >= 500) {
      // Retry on server errors
      await sleep(1000 * (i + 1));
      continue;
    }

    // Don't retry client errors
    const error = await response.json();
    throw new Error(error.error);
  }
  throw new Error('Max retries exceeded');
}