Rate limits

HTTP/1.1 429 Too Many Requests
Content-Type: application/json
Retry-After: 60

{
  "error": {
    "code": "SCORING_RATE_LIMITED",
    "message": "Too many reads in a row.",
    "action": "Give it 60 seconds and try again.",
    "retryable": true
  }
}

async function callWithBackoff<T>(fn: () => Promise<Response>): Promise<T> {
  for (let attempt = 0; attempt < 5; attempt++) {
    const res = await fn();
    if (res.ok) return res.json() as Promise<T>;

    if (res.status !== 429) {
      const body = await res.json().catch(() => ({}));
      throw new Error(body.error?.message ?? `HTTP ${res.status}`);
    }

    const retryAfter = Number(res.headers.get('Retry-After') ?? 60);
    const jitter = Math.random() * 0.25 * retryAfter;
    const delay = (retryAfter + jitter) * 1000 * Math.pow(1.5, attempt);
    await new Promise((r) => setTimeout(r, delay));
  }
  throw new Error('Exceeded max retries on 429');
}