The async stuff may require some attention, but it's part of the performance story when dealing with many requests, not when evaluating just one.

As regards configuration, all the means you could want for configuration are there. You can access items directly [1], or via strongly typed objects. These all support multiple sources of configuration data, and many means of overriding them.

I generally really don't like environment variables as they expose configured secrets to everything in the same machine / container, but we make use of the standard configuration system's environment variable overrides, but we use akv2k8s.io and thus only expose secrets to the container's entry point application.

[1] public Startup(IConfiguration config) { // injects config store var setting = config["yourConfigKey"] // ... but you now have to convert this from a string for any other datatype }