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

# Errors

> Handle validation, authentication, quota, and service errors.

Non-2xx responses use a stable error envelope:

```json theme={null}
{
  "success": false,
  "request_id": "fd3279e1-5657-466d-b98b-d9e7627e0788",
  "status": "failed",
  "risk_level": "unknown",
  "recommended_action": "flag",
  "decision_source": "signupbear_policy",
  "policy_version": "2026-07-beta-1",
  "checked_at": "2026-07-28T08:40:00.000Z",
  "processing_ms": 2,
  "error": {
    "code": "INVALID_INPUT",
    "message": "Provide at least one of 'email' or 'ip'"
  }
}
```

## Error codes

| HTTP | Code                     | Meaning                                      |
| ---- | ------------------------ | -------------------------------------------- |
| 400  | `INVALID_JSON`           | Request body is not valid JSON               |
| 400  | `INVALID_INPUT`          | A required field is missing or invalid       |
| 401  | `UNAUTHORIZED`           | Bearer authorization is missing or malformed |
| 401  | `INVALID_API_KEY`        | API key is unknown, invalid, or revoked      |
| 429  | `MONTHLY_LIMIT_EXCEEDED` | Current plan limit has been reached          |
| 500  | `INTERNAL_ERROR`         | SignupBear could not complete the check      |

## Retry guidance

* Do not retry HTTP 400 or 401 without changing the request or key.
* Wait for a new usage period or a plan change after HTTP 429.
* Retry HTTP 500 only with bounded exponential backoff.
* Always log `request_id`; never log the API key.