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

# Authentication

Obtain and refresh access tokens, authorize apps and handle login, SSO and OTP flows.

Obtain and refresh access tokens, authorize apps and handle login, SSO and OTP flows.