Set up .NET (server-side) SDK

Install-Package LaunchDarkly.ServerSdk

using LaunchDarkly.Sdk;
using LaunchDarkly.Sdk.Server;
var builder = WebApplication.CreateBuilder(args);
// This is your LaunchDarkly SDK key.
// Never hardcode your SDK key in production.
var ldConfig = Configuration.Default("YOUR_SDK_KEY");
var client = new LdClient(ldConfig);
if (client.Initialized)
{
    // For onboarding purposes only we flush events as soon as
    // possible so we quickly detect your connection.
    // You don't have to do this in practice because events are automatically flushed.
    client.Flush();
    Console.WriteLine("*** SDK successfully initialized!\n");
}
else
{
    Console.WriteLine("*** SDK failed to initialize\n");
    Environment.Exit(1);
}