Errors & rate limits

// Success
{ "success": true, "data": ..., "total": 128, "page": 1, "limit": 20 }

// Error
{ "statusCode": 401, "code": "INVALID_API_KEY", "message": "The API key is invalid." }

HTTP/1.1 200 OK
X-RateLimit-Limit: 60
X-RateLimit-Remaining: 57
X-RateLimit-Reset: 1790000000

HTTP/1.1 429 Too Many Requests
Retry-After: 18
{ "statusCode": 429, "code": "RATE_LIMITED", "message": "Rate limit exceeded (300 requests per minute)." }

async function b2bFetch(url, attempt = 0) {
  const res = await fetch(url, { headers: { 'X-API-Key': process.env.ESIMOA_PARTNER_KEY } });
  if (res.status === 429 && attempt < 3) {
    const wait = Number(res.headers.get('Retry-After') ?? 1);
    await new Promise((r) => setTimeout(r, wait * 1000));
    return b2bFetch(url, attempt + 1);
  }
  const body = await res.json();
  if (!res.ok) throw Object.assign(new Error(body.message), { code: body.code, status: res.status });
  return body;
}