API.cs

[HttpGet]
public async Task<JsonResult> Get()
{
    var users = dataContext.TrackingUsers.Include(u => u.TrackingVisits).ThenInclude(v => v.TrackingDevice);
    var newton = JsonConvert.SerializeObject(users);
    var json_net = Json(users);
    return json_net;
}

TrackingModels.cs

public class TrackingUserModel : Entity {
    public TrackingUserModel() {
        IsBanned = false;
    }
    public String Email { get; set; }
    public Boolean IsBanned { get; set; }
    public List<TrackingVisitModel> TrackingVisits { get; set; }
}

public class TrackingDeviceModel : Entity {
    public String HardwareModel { get; set; }
    public String OS { get; set; }
    public String OSVersion { get; set; }
    public List<TrackingVisitModel> TrackingVisits { get; set; }
}

public class TrackingVisitModel : Entity {
    public TrackingVisitModel() {
        DateTime = DateTime.Now;
    }
    public Guid TrackingUserId { get; set; }
    public TrackingUserModel TrackingUser { get; set; }
    
    public Guid TrackingDeviceId { get; set; }
    public TrackingDeviceModel TrackingDevice { get; set; }
    public Guid AppId { get; set; }
    public String AppVersion { get; set; }
    public DateTime DateTime { get; set; }
}