If you’re building custom applications owned by the same organization, there are many benefits of implementing single sign-on (SSO). You get shorter development time, increased security, and improved user experience. One of my favorite aspects of SSO is that instead of upgrading a large codebase all at once, you can do it a piece at a time.
What do I mean by that? Well, let's say you're looking to shift an app written in ASP.NET MVC 5 to ASP.NET Core MVC. You can do so by migrating each service at a time instead of rewriting the entire thing. You can then connect the two apps like they were one by enabling SSO.