I know I'm missing something in the details here.
Problem
Despite Googling, trying examples, different formats, etc, the AJAX request that I send always is validated as having all fields empty, but not being null.
I think I'm not sending things in the proper format for the controller to recognize it as an object but I'm not sure what.
Fiddler: What my request looks like
With some dummy data:

Code: Model Class
public class ContactUsMessage
{
public string Email { get; set; }
public string Name { get; set; }
public string PhoneNumber { get; set; }
public string Message { get; set; }
}
Code: WebAPI Controller
[HttpPost]
public HttpResponseMessage NewMessage(ContactUsMessage messageToSend)
{
if (messageToSend == null)
{
var sadResponse = Request.CreateResponse(HttpStatusCode.BadRequest, "Empty Request");
return sadResponse;
}
var messageValidator = new ContactUsMessageValidator();
var results = messageValidator.Validate(messageToSend);
var failures = results.Errors;
var sadString = "";
if (!results.IsValid)
{
foreach (var error in failures)
{
sadString += " Problem: " + error.ErrorMessage;
}
var sadResponse = Request.CreateResponse(HttpStatusCode.NotAcceptable, "Model is invalid." + sadString);
return sadResponse;
}
else
{
SendContactFormEmail(messageToSend.Email, messageToSend.Name, messageToSend.PhoneNumber, messageToSend.Message);
}
Code: JavaScript on Page
function sendSubmissionForm() {
var dataObject = JSON.stringify(
{
messageToSend: {
'Email': $('#inpEmail').val(),
'Name': $('#inpName').val(),
'PhoneNumber': $('#inpPhone').val(),
'Message': $('#inpMessage').val()
}
});
$.ajax({
url: '/api/contactus/newmessage',
type: 'POST',
done: submissionSucceeded,
fail: submissionFailed,
data: dataObject
});
}