Rate limits

Generous limits, said in every answer.

Limits are per minute, counted in windows that start on the minute.

Limit	Per minute
Requests from one app for one person (or one token)	600
Of those, requests that change something (POST, PATCH, DELETE)	120
All apps and tokens of one organisation together	3000
Recipients of mail sent through the API, per person	500 an hour

Every answer says where you stand: X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset (seconds until the window starts again). Over a limit you get 429 rate_limited with Retry-After.

Waiting it out

async function call(url, init, tries = 4) {
  const res = await fetch(url, init);
  if (res.status === 429 && tries > 0) {
    const wait = Number(res.headers.get("Retry-After") ?? 1);
    await new Promise((r) => setTimeout(r, wait * 1000));
    return call(url, init, tries - 1);
  }
  return res;
}

Polling? Don't: mail has a changes feed you can hold open, and the business apps send webhooks.