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

# Rate Limits

> How FirstSales protects API reliability.

FirstSales enforces public API rate limits by Developer API key and organization.

Read routes have higher limits than write and bulk routes. Bulk imports, lifecycle actions, and billing link creation may have stricter limits because they create downstream work.

When a request is rate limited, the API returns `429` with a stable error code.

```json theme={null}
{
  "error": {
    "code": "rate_limited",
    "message": "Too many requests. Retry later.",
    "requestId": "req_123"
  }
}
```

## Client behavior

* Back off on `429`.
* Use idempotency keys for retryable mutations.
* Prefer pagination instead of large unbounded reads.
* Avoid parallel writes against the same campaign or contact list unless your workflow is idempotent.