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

# Rate limits

> Headers and retry behavior when requests are rate limited.

When rate limiting is enabled, responses include standard limit headers.

```http theme={null}
X-RateLimit-Limit: 100
X-RateLimit-Remaining: 93
X-RateLimit-Reset: 1780070400
```

If a request is denied:

```http theme={null}
HTTP/1.1 429 Too Many Requests
Retry-After: 2
```

```json theme={null}
{
  "error": {
    "code": "RATE_LIMIT_EXCEEDED",
    "message": "too many requests"
  }
}
```

## Keying

Authenticated requests are rate-limited by API key ID. Unauthenticated requests fall back to client IP.

## Client behavior

* Back off on `429`.
* Respect `Retry-After` when present.
* Use exponential backoff for repeated limit responses.
* Avoid retry storms by preserving idempotency keys on retried `POST` requests.