This approach is suitable for all types of websites, including server-side rendered applications.
In Cookie-based authentication, Authgear returns Set-Cookie headers and sets cookies to the browser. The cookies are HTTP only and share under the same root domains. So you will need to setup the custom domain for Authgear, such as identity.yourdomain.com.
In this setting, if you have multiple applications under yourdomain.com, all applications would share the same session cookie automatically. After that, you can verify the cookies by integrating Authgear with your backend. The HTTP requests must be authenticated by Forwarding to Authgear Resolver Endpoint.