ASP.NET Core with Azure Key Vault configuration provider

Program.cs

using Microsoft.Extensions.Configuration;

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
    WebHost.CreateDefaultBuilder(args)
        .ConfigureAppConfiguration((context, config) =>
        {
            var builtConfig = config.Build();

            var keyVaultConfigBuilder = new ConfigurationBuilder();

            keyVaultConfigBuilder.AddAzureKeyVault(
                $"https://{builtConfig["Vault"]}.vault.azure.net/",
                builtConfig["ClientId"],
                builtConfig["ClientSecret"]);

            var keyVaultConfig = keyVaultConfigBuilder.Build();

            config.AddConfiguration(keyVaultConfig);
        })
        .UseStartup<Startup>();