CONCURRENT_LIMIT

Too many requests running at once for your plan. Wait a second and retry.

CONCURRENT_LIMIT caps how many requests your account can have running at once: Free 2, Starter 5, Growth 20, Scale 50, Enterprise 100. The cap is per account, not per key. Unlike RATE_LIMITED, it clears quickly: slots free up as your running requests finish.

HTTP 429. Body always includes code: "CONCURRENT_LIMIT". Branch on code, never on the human-readable message — wording can change without notice; the code is the stable contract.

{
  "status": "error",
  "code": "CONCURRENT_LIMIT",
  "message": "Too many concurrent requests for your tier (5/5 in flight). Retry in a moment.",
  "in_flight": 5,
  "limit": 5,
  "retry_after": 1
}

Back off and retry. The body always has `retry_after: 1` (seconds), plus `in_flight` and `limit`. Add some jitter so parallel workers don't all retry together. If you hit this often, cap your own concurrency at your plan's limit with a queue, or upgrade.

Suggested handling in a Node client:

if (data.code === 'CONCURRENT_LIMIT') {
  // All slots busy. retry_after is always 1 second; add jitter.
  await sleep(data.retry_after * 1000 + Math.random() * 500);
  return retry();
}

See the full error index for the complete catalog with the handling switch statement covering every code at once.