It's conceivable that you could use an iFrame on your page. Keep in mind, that from a security perspective, it's important that the users can see the URL which is requesting their username/password, and that the SSL certificate is "Green". Otherwise, how would they distinguish a login page from a phishing attack? Also, from the perspective of single sign-on, it doesn't really make sense that the login page would be different for different applications. You want your users to recognize the "legitimate" login page for your organization. For example, no matter which app you login to at Google, you see the same login page... However... if you really think that customizing a login page for a specific application makes sense... if the application is using OpenID Connect, what you could do is have the app request a specific "acr_ value". This corresponds to the name of a custom authentication script, which would enable you to present a different page for either step 1 or step 2 of the authentication workflow.