protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { try { string _reqId = HttpContext.Current.Request.Params.Get("payment-id").ToString(); //Get this params from paykun return url //string _reqId = "05745-64541-69405-82270"; PaykunPayment _payment = new Paykun.PaykunPayment("060806219399378", "C019A43EB7B95D4D7FA51D148DFE9B3D", "9DFD9CE5071C0413AB33028FEA4EC781", _isLive: true); // Change _isLive to false for sandbox mode, While using sandbox mode you will need to provide credintials for sandbox and not of live environment TransactionStatusRes transRes = _payment.GetTransactionStatus(_reqId); if (transRes.status == true) { //Request status //handle your response here if (transRes.data.transaction.status == "Failed") { //Failed transaction } else if (transRes.data.transaction.status == "Initialized") { //Initialized transaction } else if (transRes.data.transaction.status == "Success") { //Success transaction Response.Redirect("payment_success.aspx?Payment_Id=" + _reqId + ""); } } else { //Request error get here your error description string error = transRes.errors.errorMessage; // Response.Redirect("patient/payment_success.aspx?Payment_Id=" + _reqId + ""); } } catch (Exception ex) { ex.ToString(); } } }