ConfigurationHelper.cs

public static Settings Settings
{
    get
    {
        if (_settings != null)
        {
            return _settings;
        }
                
        var configurationRoot = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json")
            .AddEnvironmentVariables()
            .Build();
        _settings = new Settings();
        configurationRoot.Bind(_settings);

        return _settings;
    }
}