How to send sms from Visual Basic

The most simple way to send SMS from Visual Basic is to use the built in HTTP/Rest SMS api of Ozeki SMS Gateway. When you use this API, you will send SMS messages by issuing a HTTP Post request to the SMS gateway. The HTTP Post request will contain a message formatted in json format. The SMS gateway will send this SMS to the recipient phone, and it will return a HTTP 200 OK response to your request.

how to send an sms from visual basic
Figure 1 - How to send an SMS from Visual Basic

Visual Basic send sms code example

Imports Ozeki.Libs.Rest

Module Program
    Sub Main(args As String())

        Dim configuration As New Configuration
        configuration.Username = "http_user"
        configuration.Password = "qwe123"
        configuration.ApiUrl = ""

        Dim msg As New Message
        msg.ToAddress = "+36201111111"
        msg.Text = "Hello, World!"

        Dim api = New MessageApi(configuration)

        Dim result = api.Send(msg)


    End Sub
End Module

Download SendSms.vb

The source code explained in this article can be downloaded and used and modified free of charge.
Download: (48.6Kb)

What is in the file?

The file contains the Ozeki.Libs.Rest library, which gives you all the tools neccessary to send and receive SMS messages. You will also find the SendSms project in the zip, which contains the example code to show you how to send an SMS. This example code is listed below.

Figure 2 - What is inside

How to send SMS from Visual Basic (Quick steps)

To send SMS from Visual Basic:

  1. Install Ozeki SMS Gateway
  2. Connect Ozeki SMS Gateway to the mobile network
  3. Send a test SMS from Ozeki GUI
  4. Create a HTTP SMS API user
  5. Start Visual Studio
  6. Create a solution called Send-SMS.sln
  7. Add a Visual Basic console project: Send-SMS.vbproj
  8. Put the code into Program.vb or Send-SMS.vb
  9. Create a Visual Basic function called Send_SMS
  10. Create the SMS Json data
  11. Create a HTTP request to send the SMS
  12. Read the HTTP response
  13. Write the response on the console
  14. Check the logs in the SMS gateway

Install Ozeki SMS Gateway and create an HTTP API user

To be able to send SMS from Visual Basic, first you need to install Ozeki SMS Gateway. The SMS gateway can be installed on the same computer, where you develop your Visual Basic code in Visual studio. After installation, the next step is to connect Ozeki SMS Gateway to the mobile network. You can send a test sms from the Ozeki GUI to verify, that your mobile network connection works. The final step to prepare your environment is to create a HTTP sms api user. Create a user with a username of "http_user", and with a password of "qwe123" to make the example work without modification.

After the environment is setup, you can run your Visual Basic code.

HTTP API url to use send sms from Visual Basic

To send SMS from Visual Basic, your Visual Basic will will have to issue an HTTP request to the SMS gateway. The API url is shown below. Note that the IP address ( should be replaced to the IP address of your SMS gateway. If Ozeki SMS Gateway is installed on the same computer where the Visual Basic sms application is running, this can be If it is installed on a different computer it should be the IP address of that computer.

HTTP authentication to use send sms from Visual Basic

To authenticate the Visual Basic sms client, you need to send the username and password in a base64 encoded string to the server in a HTTP request. The format used is: base64(username+":"+password). In C# you can use the following code to do this encoding:

var encoding = Encoding.GetEncoding("iso-8859-1");
var usernamePassword = username + ":" + password;
var usernamePasswordEncoded = Convert.ToBase64String(encoding.GetBytes(usernamePassword));

For example if you encode the username 'http_user' and the password 'qwe123', you will get the following base64 encoded string: aHR0cF91c2VyOnF3ZTEyMw==. To send

HTTP request header to send SMS from Visual Basic

To send the SMS messages, you need to include the following lines as headers in the HTTP request. Note that we include a content type and an Authorization header.

Content-Type: application/json
Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==

HTTP request to send SMS from Visual Basic

To submit the SMS, your Visual Basic application will send an HTTP request similar to the one below. Note, that this requst contains a HTTP header part and a http body part. The HTTP body is a JSON encoded data string. It contains the recipient number and the messages text.

POST /api?action=sendmsg HTTP/1.1
Connection: Keep-Alive
Content-Length: 336
Content-Type: application/json
Authorization: Basic aHR0cF91c2VyOnF3ZTEyMw==

  "messages": [
      "message_id": "4b486234-1dde-4975-b233-47267e988287",
      "to_address": "+36201111111",
      "text": "Hello, World!",
      "create_date": "2021-06-11 14:19:47",
      "valid_until": "2021-06-18 14:19:47",
      "time_to_send": "2021-06-11 14:19:47",
      "submit_report_requested": true,
      "delivery_report_requested": true,
      "view_report_requested": true,
      "tags": []

HTTP response received by the Visual Basic sms example

Once the SMS gateway receives this request, it will generate a HTTP response. The HTTP response will contain a status code, to indicate whether the SMS submit request was successful or not. It will also return a JSON encoded structure to provide you useful details about the messages submission.

HTTP/1.1 200 OK
User-Agent: OZEKI 10.3.118 (
Content-Type: application/json; charset=utf8
Last-Modified: Fri, 11 Jun 2021 08:44:45 GMT
Server: 10/10.3.118
Transfer-Encoding: chunked

  "http_code": 200,
  "response_code": "SUCCESS",
  "response_msg": "Messages queued for delivery.",
  "data": {
    "total_count": 1,
    "success_count": 1,
    "failed_count": 0,
    "messages": [
        "message_id": "7e4fa89b-df8a-4267-afe3-da348bf200ef",
        "from_station": "%",
        "to_address": "+36201111111",
        "to_station": "%",
        "text": "Hello, World!",
        "create_date": "2021-06-11 14:19:47",
        "valid_until": "2021-06-18 14:19:47",
        "time_to_send": "2021-06-11 14:19:47",
        "submit_report_requested": true,
        "delivery_report_requested": true,
        "view_report_requested": false,
        "tags": [
            "name": "Type",
            "value": "SMS:TEXT"
        "status": "SUCCESS"

How to send SMS from Visual Basic (Video tutorial)

This video shows you how to create a new .Net core console project in Visual Studio, how to name it to Send-SMS.sln. Once the solution is create, you might notice that a Send-SMS.vbproj is added to the solution, and by default the Program.cs file is opened. You can rename the Program.vb to Send-SMS.vb if you wish. You will also see in the Video, how the example code below can be copied into the Send-SMS.vb file, and how it can be compiled and executed.

Video 1 - How to download and open the solution


The example code below is part of the SendSms.sln Visual Studio Solution. A visual studio solution can contain multiple projects and multiple files. In this solution there is only two projects: SendSms.vbproj, Ozeki.Libs.Rest.csproj, and one file: Program.vb.

Figure 2 - SendSms.sln

How to check that the SMS has been accepted by the HTTP user

After the SMS has been submitted, it is a good idea to check your SMS gateway, to see what it has received. You can check the log by opening the HTTP user's details from the Ozeki SMS Gateway managment console. The following video shows you what to look for.

Video 2 - Sending SMS with the Visual Basic code above

How to check that the SMS has been sent to the mobile network

The final step in verifying the procedure is to take a look at the logs of the mobile network connection. You might have to turn on logging in the configuration of the connection before you send the message to see the logs. If logging is enabled you will see the phone number and the text of the message you have sent.

Video 3 - How to turn on logging in Ozeki SMS Gateway

Runing the Visual Basic sms example on Windows

When you use windows to run this sms example written in Visual Basic, you will notice that you get slightly better performance, than when you run it on Linux. To understand why this happens, you must bring into mind that Visual Basic is using the .NET framework for code execution. This is because the .NET implementation on Windows is optimized for performance, while mono, the .NET implementation on Linux has some catching up to do in this field.


The guide above explained the steps of SMS sending from Visual Basic. Ozeki provides all the knowledge and tools to make your work easier. If the steps were followed carefully, messaging with mobile customers from VB with the help of Ozeki SMS Gateway should not be complicated. The high performance of Ozeki SMS Gateway allows you to send up to 1000 SMS per second.

Make sure that you continue reading in Ozeki's tutorial page, where there is information about similar topics, like SMS scheduling and receiving in VB.

Your next thing to do is to download Ozeki SMS Gateway and start working!

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