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

# Errors & rate limits

> Error responses of the LeakCheck API and the request-rate limits that apply.

## Errors

The API reports failures with a standard HTTP status code and an error
message describing the condition:

| Error                                         | Status code | Notes                                                      |
| --------------------------------------------- | ----------- | ---------------------------------------------------------- |
| Missing X-API-Key header                      | 401         | No API key provided in the request header.                 |
| Invalid X-API-Key                             | 400         | The API key provided is invalid.                           |
| Invalid type                                  | 400         | The `type` parameter is not one of the supported values.   |
| Invalid email                                 | 400         | The email format is incorrect.                             |
| Invalid query                                 | 400         | The query format is invalid.                               |
| Invalid domain                                | 400         | The domain format is invalid.                              |
| Too short query (\< 3 characters)             | 400         | The query must be at least 3 characters long.              |
| Invalid characters in query                   | 400         | The query contains characters that are not allowed.        |
| Too many requests                             | 429         | You have exceeded the rate limit — see below.              |
| Active plan required                          | 403         | A paid plan is required to make this request.              |
| Limit reached                                 | 403         | You have reached your plan's usage quota.                  |
| Could not determine search type automatically | 422         | Auto-detection failed — pass an explicit `type` parameter. |

Handle `429` responses by backing off and retrying; treat `403` as a signal
to check your plan status or remaining quota (the `quota` field of every
successful response tells you how many queries you have left).

## Rate limits

| API        | Limit               | Notes                                              |
| ---------- | ------------------- | -------------------------------------------------- |
| Pro API v2 | 3 requests / second | Applies to any plan; can be increased in settings. |
| Public API | 1 request / second  | Fixed.                                             |

By default, the Pro API is limited to 3 requests per second on any plan. You
can increase this limit in your account settings.