How to send multiple sms from C#

The simplest way to send SMS from C# 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.

send multiple sms from
Figure 1 - Send multiple sms from C#

C# code to send multiple sms to mobile

The C# sms code sample below demonstrates how you can send SMS using the http rest sms api of Ozeki SMS Gateway using the C# Ozeki.Libs.Rest library. This library is provided to you free of charge, and you may use it and modify it in any of your projects.

SendSMS.cs 
using Ozeki.Libs.Rest;
using System;

namespace SendMultipleSms
{
    class Program
    {
        static void Main(string[] args)
        {
            var configuration = new Configuration()
            {
                Username = "http_user",
                Password = "qwe123",
                ApiURL = "http://127.0.0.1:9509/api"
            };

            var msg1 = new Message()
            {
                ToAddress = "+36201111111",
                Text = "Hello, World 1"
            };

            var msg2 = new Message()
            {
                ToAddress = "+362222222",
                Text = "Hello, World 2"
            };

            var msg3 = new Message()
            {
                ToAddress = "+363333333",
                Text = "Hello, World 3"
            };

            var api = new MessageApi(configuration);

            var result = api.Send(new Message[]{ msg1, msg2, msg3 });

            Console.WriteLine(result);
            Console.ReadKey();
        }
    }
}

How to use the C# sms example:

This C# sms example can be used in any .NET or .NET core application. To use it, you must add the Ozeki.Libs.Rest dll as a reference to your project. After the project reference is added, you must put the using Ozeki.Libs.Rest; directive into the header section of your C# source code. This will allow you to use the classes provided by the Ozeki.Libs.Rest library. You can use the Message class to create the SMS. You can use the MessageApi class to send the SMS to the SMS gateway. The SMS gateway will forward your message to the mobile network either through a wireless connection or through the Internet.

Download SendSMS.cs

The source code explained in this article can be downloaded and used and modified free of charge.
Download: SendMultipleSms.cs.zip (34.5Kb)

What is in the SendMultipleSms.cs file?

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

send multiple sms cs directory
Figure 2 - What is inside SendMultipleSms.cs.zip

How to send multiple sms from C# (Quick steps)

To send multiple sms from C#:

  1. Setup Visual Studio Community
  2. Download the Send-multiple-SMS.cs.zip file
  3. Extract the .zip file from Downloads folder
  4. Open the SendMultipleSms.sln file in Visual Studio
  5. Launch Ozeki SMS Gateway
  6. Create a HTTP API user in Ozeki
  7. Run Program.cs C# code in Visual Studio to send test SMS messages
  8. Check the Sent box in Ozeki SMS Gateway

Install Ozeki SMS Gateway and create an HTTP API user

To be able to send SMS from C#, first you need to install Ozeki SMS Gateway. The SMS gateway can be installed on the same computer, where you develop your C# 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 C# code.

HTTP API url to use send sms from C#

To send SMS from C#, your C# will have to issue an HTTP request to the SMS gateway. The API url is shown below. Note that the IP address (127.0.0.1) should be replaced to the IP address of your SMS gateway. If Ozeki SMS Gateway is installed on the same computer where the C# sms application is running, this can be 127.0.0.1. If it is installed on a different computer, it should be the IP address of that computer. 

http://127.0.0.1:9509/api?action=rest

HTTP authentication to use send sms from C#

To authenticate the C# 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 C#

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 C#

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

POST /api?action=sendmsg HTTP/1.1
Connection: Keep-Alive
Content-Length: 979
Content-Type: application/json
Authorization: Basic aHR0cF91c2VyOnF3ZTEyMw==
Host: 127.0.0.1:9511

{
  "messages": [
    {
      "message_id": "49aa6f3a-5d2a-4d53-bd63-9eb9da8bb23e",
      "to_address": "+36201111111",
      "text": "Hello, World 1",
      "create_date": "2021-06-11 13:08:26",
      "valid_until": "2021-06-18 13:08:26",
      "time_to_send": "2021-06-11 13:08:26",
      "submit_report_requested": true,
      "delivery_report_requested": true,
      "view_report_requested": true,
      "tags": []
    },
    {
      "message_id": "62098595-5ff8-4ca8-8b06-54f0fb31ee12",
      "to_address": "+362222222",
      "text": "Hello, World 2",
      "create_date": "2021-06-11 13:08:26",
      "valid_until": "2021-06-18 13:08:26",
      "time_to_send": "2021-06-11 13:08:26",
      "submit_report_requested": true,
      "delivery_report_requested": true,
      "view_report_requested": true,
      "tags": []
    },
    {
      "message_id": "f5b576ff-52b8-4de0-9677-4731769198f9",
      "to_address": "+363333333",
      "text": "Hello, World 3",
      "create_date": "2021-06-11 13:08:26",
      "valid_until": "2021-06-18 13:08:26",
      "time_to_send": "2021-06-11 13:08:26",
      "submit_report_requested": true,
      "delivery_report_requested": true,
      "view_report_requested": true,
      "tags": []
    }
  ]
}

HTTP response received by the C# 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 message's submission. 

HTTP/1.1 200 OK
User-Agent: OZEKI 10.3.116 (www.myozeki.com)
Content-Type: application/json; charset=utf8
Last-Modified: Fri, 11 Jun 2021 13:06:37 GMT
Server: 10/10.3.116
Transfer-Encoding: chunked

{
  "http_code": 200,
  "response_code": "SUCCESS",
  "response_msg": "Messages queued for delivery.",
  "data": {
    "total_count": 3,
    "success_count": 3,
    "failed_count": 0,
    "messages": [
      {
        "message_id": "49aa6f3a-5d2a-4d53-bd63-9eb9da8bb23e",
        "from_station": "%",
        "to_address": "+36201111111",
        "to_station": "%",
        "text": "Hello, World 1",
        "create_date": "2021-06-11 13:08:26",
        "valid_until": "2021-06-18 13:08:26",
        "time_to_send": "2021-06-11 13:08:26",
        "submit_report_requested": true,
        "delivery_report_requested": true,
        "view_report_requested": false,
        "tags": [
          {
            "name": "Type",
            "value": "SMS:TEXT"
          }
        ],
        "status": "SUCCESS"
      },
      {
        "message_id": "62098595-5ff8-4ca8-8b06-54f0fb31ee12",
        "from_station": "%",
        "to_address": "+362222222",
        "to_station": "%",
        "text": "Hello, World 2",
        "create_date": "2021-06-11 13:08:26",
        "valid_until": "2021-06-18 13:08:26",
        "time_to_send": "2021-06-11 13:08:26",
        "submit_report_requested": true,
        "delivery_report_requested": true,
        "view_report_requested": false,
        "tags": [
          {
            "name": "Type",
            "value": "SMS:TEXT"
          }
        ],
        "status": "SUCCESS"
      },
      {
        "message_id": "f5b576ff-52b8-4de0-9677-4731769198f9",
        "from_station": "%",
        "to_address": "+363333333",
        "to_station": "%",
        "text": "Hello, World 3",
        "create_date": "2021-06-11 13:08:26",
        "valid_until": "2021-06-18 13:08:26",
        "time_to_send": "2021-06-11 13:08:26",
        "submit_report_requested": true,
        "delivery_report_requested": true,
        "view_report_requested": false,
        "tags": [
          {
            "name": "Type",
            "value": "SMS:TEXT"
          }
        ],
        "status": "SUCCESS"
      }
    ]
  }
}

C# sms example: SendMultipleSms.sln

How to download the SendMultipleSMS.sln project (Video tutorial)

In the following video, you will learn about how you can use the SendMultipleSMS.sln C# project. The video will start with the download page and will take you all the way to the opened code editor panel. You will learn how to download and open the code file. The video is only 54 second long but it has all the necessary information you need to successfully use the example code file.

Video 1 - How to download and open the solution above (Video tutorial)

The example code below is part of the SendMultipleSms.sln Visual Studio Solution. A visual studio solution can contain multiple projects and multiple files. In this solution there is only one project: SendMultipleSms.csproj, and one file: Program.cs.

how to send multiple sms using c sharp
Figure 3 - SendMultipleSms.sln

How to use the project (Video tutorial)

In the following clip, you will see how you can launch the SendMultipleSMS.cs C# code. The video will start with the opened code and will take you all the way to the events tab with the log of the sent message. You will see how to launch the code and what happened if the code was executed. The video is a little shorter than 1 minute but it contains all the information that is necessary to run the project.

Video 2 - How to use the SendMultipleSms.cs solution (Video tutorial)

Runing the C# sms example on Windows

When you use windows to run this sms example written in C#, 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 C# 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.

Conclusion

This article showed the steps of multiple SMS sending in one request from C#. With this knowledge and the provided tools, you should be able to reach out to several customers with one single code. Ozeki SMS Gateway has an important part in this process because this program organizes the message delivery. Ozeki SMS Gateway works with high quality and performance, allowing you to send up to 1000 SMS per second.

Continue your learning in Ozeki's tutorial pages, where you can read about topics like SMS scheduling and deleting in C#.

Now your only thing to do is to download Ozeki SMS Gateway and start working!

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