Recently, a task was given to me at work where we needed a multisite configuration. We all know that multi-environment is as easy as appsettings.<environment_name>.config. What about in multi-tenant environments? You can't have appsettings.site1.config and appsettings.site2.config in your site! Well, not without a little extra work... Allow me to introduce AddKeyPerFile ; this handy little function that you set up in your Program.cs will enumerate the files in a directory and add them to your Configuration. "Alright!" you must be thinking "Show me how this miracle function works..." Well, let's get to it! First, you'll want to identify the config sections that will be unique to each site and put them in their own folder. I do this by site name because it makes the most sense by our conventions, if something else works for your practice, these names aren't set in stone. Now, in order to suck those values into your config, there's one simp