The book covers how to handle and fix mistakes while resending confirmation tokens in order to address typical problems with token validation and user authentication difficulties in an ASP.NET Core application.

There are special difficulties when deploying an ASP.NET Core application to Azure, especially when integrating SMTP functionalities. Even with successful local tests, there are times when deploying to Azure necessitates extra parameters, such safely handling passwords and controlling network access.

In ASP.NET, using custom validation attributes is a clever way to enforce business rules, like not allowing duplicate user registrations. By using dependency injection to integrate services, this technique enables characteristics to dynamically interact with application data.