Search gstin with API

Sir;

How to use your API for search GST Number details with vb6, I used 

httpObject.Open "get", "https://www.knowyourgst.com/developers/gstincall/?gstin=gst-number" method

Code used:

Const HTTPREQUEST_PROXYSETTING_DEFAULT = 0
Const HTTPREQUEST_PROXYSETTING_PRECONFIG = 0
Const HTTPREQUEST_PROXYSETTING_DIRECT = 1
Const HTTPREQUEST_PROXYSETTING_PROXY = 2

Const HTTPREQUEST_SETCREDENTIALS_FOR_SERVER = 0
Const HTTPREQUEST_SETCREDENTIALS_FOR_PROXY = 1

Dim httpObject As New WinHttp.WinHttpRequest

Private Sub cmdSend_Click()
On Error GoTo Handler
Dim passthrough As String
httpObject.Open "get", "https://www.knowyourgst.com/developers/gstincall/?gstin=gst-number"
passthrough = "API_KEY"
httpObject.Send

MsgBox httpObject.ResponseText
Set httpObject = Nothing
Exit Sub

Handler:
MsgBox Err.Description
End Sub

Function getdata(url As String, data As String) As String
Dim WinHttpReq As Object, status As String, response As String
On Error GoTo errorfound
Set WinHttpReq = CreateObject("WinHttp.WinHttpRequest.5.1")
WinHttpReq.Open "get", url, False
WinHttpReq.Send data
getdata = WinHttpReq.status & " ? " & WinHttpReq.StatusText & " ? " & WinHttpReq.ResponseText
Exit Function
errorfound:
getdata = Err.Description
End Function

sorry nothing can found ; please help me out

thank you

with regrads

samim