> For the complete documentation index, see [llms.txt](https://docs.esimpay.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.esimpay.net/eng/api/headers.md).

# Headers

| Header           | Description                                  |
| ---------------- | -------------------------------------------- |
| `CF-MERCHANT-ID` | Merchant identifier                          |
| `CF-ACCESS-SIGN` | HMAC-SHA256 signature (see `/customer/sign`) |