Rate Limiting

X-RateLimit-Limit: 400
X-RateLimit-Remaining: 375
X-RateLimit-Cost: 5

HTTP/1.1 429 Too Many Requests
Retry-After: 3
X-RateLimit-Limit: 400
X-RateLimit-Remaining: 0
X-RateLimit-Cost: 20

async function requestWithBackoff(url, options, maxRetries = 3) {
  for (let attempt = 0; attempt < maxRetries; attempt++) {
    const response = await fetch(url, options);

    if (response.status !== 429) return response;

    const retryAfterSec = parseInt(response.headers.get('Retry-After'), 10) || 0;
    const backoffSec = Math.pow(2, attempt);
    const waitSec = Math.max(retryAfterSec, backoffSec);
    await new Promise(resolve => setTimeout(resolve, waitSec * 1000));
  }
  throw new Error('Max retries exceeded');
}