# Missing client ID

Resolve missing client ID errors.

The request does not include an `X-Client-Id` header and no `X-Token` was provided either.

Client-side requests must include either `X-Client-Id` or `X-Token`.

## Response

All error responses follow the [Problem Details (RFC 9457)](/reference/api/overview#errors) format. The `type`, `title`, `status`, and `detail` fields are always present, while `instance` may be omitted depending on the API.

Here is an example of the response returned for this error:

```json
{
  "type": "https://croct.help/api/authentication/missing-client-id",
  "title": "The client ID is missing.",
  "status": 401,
  "detail": "The request must include a client ID, but none was provided.",
  "instance": "/client/web/content"
}
```