> For the complete documentation index, see [llms.txt](https://kasplo.gitbook.io/kasplo-doc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kasplo.gitbook.io/kasplo-doc/channels/email-marketing/api-authentication.md).

# API Authentication

### Authentication

All API requests require two headers for authentication:

* sid: Your Secret ID
* **api-key:** Your API Key

Example Header:

```
api-key: {api-key}
```

Note: Replace **{sid}** and **{api-key}** with your actual credentials.