I understand implementing custom login pages in my apps, and how those hang together. My use case is to have a single custom complex branded login page to replace the Okta login page. The intention here is to have a specific branding and look and feel for a central login page for all applications, rather than have each application build their own custom login page.

I can see how I could define an IdP and use either the default routing rules, or the idp parameter in the OIDC calls to route the request, but I'd like to avoid the complication of my central login page function having to mint tokens.

So the use case is Okta recieves the OIDC call or SAML request and instead of presenting the user with the Okta standard login page, redirects the user to https://myapp/login which handles the authentication for the user, sends them back to Okta with a session and Okta then honours the original SAML request ( ACS URL redirect ) or OIDC call ( redirect_uri ) to the target application.