> For the complete documentation index, see [llms.txt](https://developers.crawlbyte.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developers.crawlbyte.ai/authentication.md).

# Authentication

## How Authentication Works

* Include your API Key in the Request Headers for every API call:

```
Authorization: YOUR_API_KEY_HERE
Content-type: application/json
```

### Error Responses

* If authentication fails, you'll receive one of these error responses:

```
401 Unauthorized: Invalid or missing API key
403 Forbidden: API key valid but insufficient permissions
429 Too Many Requests: Rate limit exceeded for your API key — check your current package or Pay-as-you-go limits to view your allowed requests per second
```