How to Send a Message by WhatsApp API using vbnet

Send a Message by WhatsApp API using vbnet-ultramsg
Contents hide
1 Introduction
2 First WhatsApp API Message Using Visual Basic.NET
3 Send Image using vbnet
4 Send Document using vbnet
5 Send Audio using vbnet
6 Send Voice using vbnet
7 Send Video using vbnet
8 Send Link using vbnet
9 Send Contact using vbnet
10 Send Location using vbnet
11 Send Vcard using vbnet

Introduction

In this tutorial, we will create a page to send WhatsApp message via WhatsAppAPI using vb.net

First WhatsApp API Message Using Visual Basic.NET

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/chat"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&body=WhatsApp API on UltraMsg.com works good"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
       'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length) 
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/chat"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&body=WhatsApp API on UltraMsg.com works good"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
       'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length) 
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

Send Image using vbnet 

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/image"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&image=https://file-example.s3-accelerate.amazonaws.com/images/test.jpeg&caption=image Caption"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/image"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&image=https://file-example.s3-accelerate.amazonaws.com/images/test.jpeg&caption=image Caption"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

Send Document using vbnet

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/document"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&filename=hello.pdf&document=https://file-example.s3-accelerate.amazonaws.com/documents/cv.pdf"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/document"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&filename=hello.pdf&document=https://file-example.s3-accelerate.amazonaws.com/documents/cv.pdf"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

Send Audio using vbnet

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/audio"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&audio=https://file-example.s3-accelerate.amazonaws.com/audio/2.mp3"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/audio"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&audio=https://file-example.s3-accelerate.amazonaws.com/audio/2.mp3"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

Send Voice using vbnet

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/voice"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&audio=https://file-example.s3-accelerate.amazonaws.com/voice/oog_example.ogg"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/voice"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&audio=https://file-example.s3-accelerate.amazonaws.com/voice/oog_example.ogg"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

Send Video using vbnet

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/video"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&video=https://file-example.s3-accelerate.amazonaws.com/video/test.mp4"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/video"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&video=https://file-example.s3-accelerate.amazonaws.com/video/test.mp4"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

Send Link using vbnet

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/link"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&link=https://en.wikipedia.org/wiki/COVID-19"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/link"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&link=https://en.wikipedia.org/wiki/COVID-19"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

Send Contact using vbnet

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/contact"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&contact=14000000001@c.us"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/contact"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&contact=14000000001@c.us"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

Send Location using vbnet

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/location"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&address=ABC company \n Sixth floor , office 38&lat=25.197197&lng=55.2721877"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/location"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&address=ABC company \n Sixth floor , office 38&lat=25.197197&lng=55.2721877"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

Send Vcard using vbnet

Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/vcard"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&vcard= BEGIN:VCARD\nVERSION:3.0\nN:lastname;firstname\nFN:firstname lastname\nTEL;TYPE=CELL;waid=14000000001:14000000002\nNICKNAME:nickname\nBDAY:01.01.1987\nX-GENDER:M\nNOTE:note\nADR;TYPE=home:;;;;;;\nADR;TYPE=work_:;;;;;;\nEND:VCARD"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module  
Imports System 
Imports System.Net
Imports System.Text
Imports System.IO
Imports System.Web

Module base64  
    Sub Main()  
        Dim WebRequest As HttpWebRequest
        Dim instance_id as string ="instance1150"
        Dim token as string  ="1g55hyy7ixrsi2"
        Dim mobile_number as string  ="14155552671"
        dim ultramsgApiUrl as string  ="https://api.ultramsg.com/"+instance_id+"/messages/vcard"
        WebRequest = HttpWebRequest.Create(ultramsgApiUrl)
        Dim postdata As String = "token=" + token + "&to="+ mobile_number + "&vcard= BEGIN:VCARD\nVERSION:3.0\nN:lastname;firstname\nFN:firstname lastname\nTEL;TYPE=CELL;waid=14000000001:14000000002\nNICKNAME:nickname\nBDAY:01.01.1987\nX-GENDER:M\nNOTE:note\nADR;TYPE=home:;;;;;;\nADR;TYPE=work_:;;;;;;\nEND:VCARD"
        Dim enc As UTF8Encoding = New System.Text.UTF8Encoding()
        Dim postdatabytes As Byte()  = enc.GetBytes(postdata)
        WebRequest.Method = "POST"
        WebRequest.ContentType = "application/x-www-form-urlencoded"
        WebRequest.GetRequestStream().Write(postdatabytes)
'WebRequest.GetRequestStream().Write(postdatabytes, 0, postdatabytes.Length)
        Dim ret As New System.IO.StreamReader(WebRequest.GetResponse().GetResponseStream())
        console.writeline(ret.ReadToEnd())
    End Sub  
  
End Module

finally, you can see Full Whatsapp API Documentation and FAQ.