Default rate limit is 1000 requests per hour per API key on the Starter plan, 10,000 on Plus, 100,000 on Team. Bursts up to 50 requests per second are tolerated as long as you don't sustain them.
When you hit the limit you get a 429 with `retry-after` set to the seconds until the bucket refills. The Node SDK auto-retries; if you're rolling your own client, honour the header.
Long-running operations (Summarize, Translate, OCR) count once per request, not per-page, so you can batch large files without exhausting the quota.