# rate_limited

Per-key rate limit exceeded. What causes the BioFlow API's rate_limited error (HTTP 429) and how to fix it.

HTTP 429 · `application/problem+json` · Per-key rate limit exceeded.

## What causes it

- The per-key burst limit was exceeded (Creator 60 requests/min, Pro 120 requests/min).

## How to fix it

- Back off and retry after the window resets — the `RateLimit` response header (IETF draft-11) tells you the remaining budget and reset time.
- Spread bursts out, or split workloads across keys.

## Example response body

```json
{
  "type": "https://getbioflow.com/docs/api/errors/rate-limited",
  "title": "Per-key rate limit exceeded",
  "status": 429,
  "instance": "urn:request:req_01abc",
  "code": "rate_limited",
  "request_id": "req_01abc"
}
```

Branch on the stable `code` field — `title` and `detail` are for humans and may
change. `type` (`https://getbioflow.com/docs/api/errors/rate-limited`) always resolves to this page. Quote
`request_id` when contacting support. Full code registry on the
[API docs hub](/docs/api#errors); the complete surface is in the
[interactive reference](/docs/api-reference).