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

# Authentication

Most endpoints require an `api_key` header with your Cekat API key. The `/register` endpoint uses `x-partner-api-key` for partner-level authentication.