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

# Error Handling

The API uses standard HTTP status codes to indicate success or failure:

* 2xx: Success
* 400: Bad request (invalid parameters)
* 401: Unauthorized (invalid token)
* 404: Resource not found
* 429: Rate limit or usage quota exceeded
* 500: Server error

Usage quota errors include a stable `error.type` value and reset details:

```json theme={null}
{
  "error": {
    "type": "quota_exceeded",
    "message": "You've reached your free tier note creation limit for this month",
    "details": {
      "current_plan": "free",
      "limit": 25,
      "used": 25,
      "reset_time": "2026-08-01T00:00:00+00:00"
    }
  }
}
```

Treat `error.type` as the machine-readable value. Messages are intended for
people and may change. A quota response also includes `Retry-After`, expressed
in seconds, when the reset time is valid.