The project I’m working on is in a maturing state. This means it needs to remain stable while still delivering new features. This is where feature toggles come into play. By adding these toggles and conditional execution paths to your code, you can keep the functionality unchanged until you turn a toggle on and then return to the previous behavior by turning it off again.

In the Azure ecosystem, we have the App Configuration resource with fairly basic feature toggle capabilities, so that’s what I’m using because it fits our current needs.

July 2026 update

There is no need to create your own App Configuration emulator image for macOS anymore.
The team has pushed an official image to the MCR.

https://mcr.microsoft.com/en-us/artifact/mar/azure-app-configuration/app-configuration-emulator/tags amd64 arch image has been released!

Setup in Aspire

For ease of local development, we use Aspire. To enable App Configuration, you’ll need the Aspire.Hosting.Azure.AppConfiguration package.
This lets you add a new resource to the AppHost: var appConfig = builder.AddAzureAppConfiguration("config");.

On your local machine, you probably don’t want to use an actual Azure resource, but an emulator. This can be configured using these lines of code:

appConfig.RunAsEmulator(emulator =>
{
    emulator.WithLifetime(ContainerLifetime.Persistent);
    emulator.WithDataVolume();
});

This works like a charm on Windows.
If you’re on Apple Silicon, like I am, it won’t.