Authenticate an Azure AD user with SAML for ASP.NET Core

The other day I needed a test application to try something with SAML support in Azure Active Directory. I started looking how to configure an ASP.NET Core webapplication to support SAML. It’s very easy to set it up for OIDC authentication but I found out ASP.Net (core) doesn’t support SAML out of the box. Google to the rescue and ignoring the blogpost from my colleague Christos (he’s wrong, it’s WS-Fed not SAML he’s using in his blogpost) , I found a few 3rd parties who build support for ASP.