Send WhatsApp Messages in C# using Visual Studio 2019 - Complete Guide

Automate WhatsApp messaging using C# .NET and the WhatsMate WA Gateway REST API

Posted on February 24, 2016   Share on Facebook Share on LinkedIn Share on Twitter Share on Google+

Last reviewed: January 28, 2026  

🚀 Automate WhatsApp Messaging with C# .NET

Looking to integrate WhatsApp messaging into your .NET applications? This guide walks you through sending WhatsApp messages using C# and the WhatsMate WA Gateway REST API. Perfect for .NET developers building Windows applications, services, or enterprise solutions with Visual Studio 2019.

Note for Visual Studio 2022 users: If you’re using Visual Studio 2022, please refer to this updated tutorial instead.

đź“‹ Prerequisites

Before you begin, ensure you have:

  1. A WhatsMate WA Gateway account - Required for API access
  2. Recipient registration - Each recipient must register with the Gateway first
  3. Visual Studio 2019 - Community, Professional, or Enterprise edition
  4. .NET Framework - Version 4.5 or higher
  5. Basic C# knowledge - Familiarity with Visual Studio and C# development

⚠️ Important: Recipients must register with the WhatsMate WA Gateway before they can receive messages. Unregistered users will not receive any messages from the Gateway. Registration instructions are available on the official WhatsMate site.

🎥 Video Walkthrough

đź“ť Step-by-Step Implementation

Follow these steps to send your first WhatsApp message from a C# application:

1. Copy the C# Template

Start by copying the following source code to the main class in your Console Application in Visual Studio:

2. Configure a few Parameters

Customize these key parameters in the C# code:

  • Line 10: Replace with your gateway instance ID
  • Lines 11-12: Update with your Client ID and Secret
  • Line 19: Specify the target phone number (including the country code) and your message content

3. Add Required Reference

Add the “System.Web.Extensions” reference to your project:

  1. Right-click on your project node in the Solution Explorer panel
  2. Choose “Add” → “Reference…”
  3. Select “Framework” on the left pane
  4. Find “System.Web.Extensions” in the middle pane and check the checkbox
  5. Click OK to add the reference

4. Build and Run

Build and run your application in Visual Studio to deliver your WhatsApp message.

🔧 Common Use Cases

This C# integration approach is ideal for:

  • Windows desktop applications - Add messaging features to WinForms or WPF apps
  • Windows services - Send notifications from background services
  • Enterprise systems - Integrate WhatsApp into business applications
  • Automated workflows - Trigger messages from scheduled tasks or events

🚀 Get Started Today

Ready to integrate WhatsApp messaging into your .NET applications? You’ll need a trial account to access the API. Sign up for a 2-week trial and start sending messages within minutes!

Next Steps: Once you’ve mastered basic message sending, explore advanced features like sending images, documents, or group messages through the WhatsMate API documentation.