# 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
```