> ## Documentation Index
> Fetch the complete documentation index at: https://docs.letterbucket.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Rate limits

> Per-key request limits across minute, hour and day windows.

Requests are rate limited per API key across three independent windows — minute, hour and day.
If any window is exceeded, the API returns `429`.

## Limits

| Window     | Default | Bulk create (`POST /subscribers/bulk`) |
| ---------- | ------- | -------------------------------------- |
| Per minute | 60      | 10                                     |
| Per hour   | 500     | 100                                    |
| Per day    | 3000    | 500                                    |

<Note>
  Limits are tracked per API key. Always respect the `Retry-After` header on a `429` before retrying.
</Note>

## Rate limited response

```json 429 Too Many Requests theme={null}
{
  "success": false,
  "code": "rate_limit_exceeded",
  "message": "Too many requests. Please try again later.",
  "errors": { "retry_after": 42 }
}
```