> For the complete documentation index, see [llms.txt](https://docs.receipthero.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.receipthero.io/merchant-api-group/authentication.md).

# Authentication

Merchant API is authenticated with RECEIPTHERO\_API\_KEY

```http
HTTP_AUTHORIZATION Token <RECEIPTHERO_API_KEY>
```