private const string URL = "https://sub.domain.com/objects.json";
    private string urlParameters = "?api_key=123";
    HttpClient client = new HttpClient();
    client.BaseAddress = new Uri(URL);
    
    // Add an Accept header for JSON format.
    client.DefaultRequestHeaders.Accept.Add(
    new MediaTypeWithQualityHeaderValue("application/json"));
    
    // List data response.
    HttpResponseMessage response = client.GetAsync(urlParameters).Result;  // Blocking call! Program will wait here until a response is received or a timeout occurs.
    if (response.IsSuccessStatusCode)
    {
        // Parse the response body.
        var dataObjects = response.Content.ReadAsAsync<IEnumerable<DataObject>>().Result;  //Make sure to add a reference to System.Net.Http.Formatting.dll
        foreach (var d in dataObjects)
        {
            Console.WriteLine("{0}", d.Name);
        }
    }
    else
    {
        Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
    }
    
    // Make any other calls using HttpClient here.
    
    // Dispose once all HttpClient calls are complete. This is not necessary if the containing object will be disposed of; for example in this case the HttpClient instance will be disposed automatically when the application terminates so the following call is superfluous.
    client.Dispose();