> For the complete documentation index, see [llms.txt](https://circleci.com/docs/llms.txt)

# User authentication

CircleCI Server currently supports OAuth through GitHub or GitHub Enterprise.

The default method for user account authentication in CircleCI Server is through GitHub.com/GitHub Enterprise OAuth.

Once your installation is up and running, provide users with a link to access the CircleCI application. For example, share `<your-circleci-hostname>.com`. Your users will be prompted to set up an account by running through the GitHub/GitHub Enterprise OAuth flow before being redirected to the CircleCI login screen.