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

# unauthorized

> Error: invalid or missing API key

# unauthorized

<Info>HTTP Status: **401 Unauthorized**</Info>

## Example response

```json theme={null}
{
  "error": {
    "code": "unauthorized",
    "message": "Invalid or missing API key",
    "docs_url": "https://docs.avatcado.com/errors/unauthorized"
  },
  "meta": {
    "request_id": "550e8400-e29b-41d4-a716-446655440000"
  }
}
```

## What happened?

The API could not authenticate your request. This happens when:

* No `Authorization` header is present
* The header format is wrong (not `Bearer <key>`)
* The API key doesn't match any active key in the system
* The API key has been revoked or deactivated

## How to fix

1. **Add the Authorization header** with the `Bearer` scheme:
   ```bash theme={null}
   curl -H "Authorization: Bearer avat_live_your_api_key" \
     "https://api.avatcado.com/v1/validate?vat_number=NL123456789B01"
   ```
2. **Check your key**: Make sure you're using the complete key, including the `avat_live_` prefix
3. **Generate a new key** if you've lost your original. Keys are stored as SHA-256 hashes and cannot be recovered

## Common mistakes

* **Missing `Bearer` prefix**: `Authorization: avat_live_xxx` won't work, it must be `Authorization: Bearer avat_live_xxx`
* **Extra whitespace**: Check for trailing spaces or newlines in your key
* **Using a revoked key**: If you've regenerated your key, the old one no longer works
* **Environment mismatch**: Make sure you're using the right key for the right environment

## Catching this error with the SDKs

<CodeGroup>
  ```typescript @avatcado/node theme={null}
  import Avatcado, { AuthenticationError } from '@avatcado/node';

  const avatcado = new Avatcado('avat_live_your_api_key');
  const { data, error } = await avatcado.vat.validate({ vatNumber: '...' });

  if (error instanceof AuthenticationError) {
    console.log(error.message);
  }
  ```

  ```python Python theme={null}
  from avatcado import Avatcado, AuthenticationError

  avatcado = Avatcado("avat_live_your_api_key")

  try:
      result = avatcado.vat.validate("...")
  except AuthenticationError as e:
      print(e.message)
  ```
</CodeGroup>

## Related errors

* [`rate_limit_exceeded`](/errors/rate_limit_exceeded) - Key is valid but quota is used up