ConfigureAppConfiguration
ASP.NET Core Configuration
Introduction ASP.NET Core configuration differs greatly from standard ASP.NET. Instead of web.config or any other way to set up the configuration we use built-in Configuration framework that comes with ASP.NET Core. It is still key-value pairs collection at the end, but we can obtain those values from various sources. One of default sources is appsettings.json file that comes with all templates. ASP.NET Core 2 templates have configuration already filled with values from appsettings.json file, along with few other sources. However, we can use and combine various sources for configuration settings (values):