using System;

using System.Text;

using System.Net.Http;

using System.Net.Http.Headers;

using Newtonsoft.Json;

​

var baseAddress = new Uri("https://api.openrouteservice.org");

​

using (var httpClient = new HttpClient{ BaseAddress = baseAddress })

{

  httpClient.DefaultRequestHeaders.Clear();

  httpClient.DefaultRequestHeaders.TryAddWithoutValidation("accept", "application/json, application/geo+json, application/gpx+xml, img/png; charset=utf-8");

  httpClient.DefaultRequestHeaders.Authorization =

      new AuthenticationHeaderValue("Bearer", "5b3ce3597851110001cf6248b66da28097c6468e84983bc0468fbf6b");

    // quotes might have to be escaped

    using (var content = new StringContent("{\"coordinates\":[[8.681495,49.41461],[8.686507,49.41943],[8.687872,49.420318]]}", Encoding.UTF8, "application/json"))

    {

      using (var response = await httpClient.PostAsync("/v2/directions/driving-car", content))

      {

        string responseData = await response.Content.ReadAsStringAsync();

        var data = JsonConvert.DeserializeObject(responseData);

        var serialised = JsonConvert.SerializeObject(data);

        Console.WriteLine(serialised);

      }

  }

}