> For the complete documentation index, see [llms.txt](https://document.ucall.vn/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://document.ucall.vn/gioi-thieu-tinh-nang-1/gioi-thieu-chung/su-dung-api-key.md).

# Sử dụng API Key