public HttpResponseMessage validateBookID(string bookID) { ReturnData rd = new ReturnData(); BookDetails b = new BookDetails(); rd = b.validateBookID(bookID); string yourJson = JsonConvert.SerializeObject(rd);; var response = this.Request.CreateResponse(HttpStatusCode.OK); response.Content = new StringContent(yourJson, Encoding.UTF8, "application/json"); return(response); }