WhatsApp API with C# .NET

This guide provides everything you need to send messages, build bots, and automate communication using the WhatsApp API C# (also known as C# WhatsApp API). We'll provide production-ready code examples and best practices using SendZen.io to ensure a world-class developer experience.

Whether you want to write a simple C# console application to send WhatsApp message C# or build a sophisticated Chatbot WhatsApp C#, you're in the right place. Unofficial libraries that rely on web scraping are unreliable and will get your number banned. Using the official WhatsApp Business API C# is the only stable and scalable method for professional applications.

SendZen makes the WhatsApp API integration C# incredibly simple. This guide covers everything from basic messaging to building complete WhatsApp bots and WhatsApp API integration in C#. Let's dive in.

This guide covers:

Send WhatsApp message C# - Complete API integration examples.

Receiving messages using an ASP.NET Core webhook.

Create WhatsApp bot C# - Build interactive bots from scratch.

WhatsApp API C# GitHub - Production-ready code examples.

Best practices for production, including WhatsApp business API integration C#.

Prerequisites

Before you start, you'll need:

.NET 6.0+ or .NET 7.0+ installed.

A free SendZen.io Account to get your API Key.

For the webhook examples, we'll use ASP.NET Core. Create a new project:

Part 1: How to Send a WhatsApp Message with C#

Sending a transactional message programmatically, like an order confirmation or a 2FA code, is a core use case. This guide shows you how to send WhatsApp message programmatically C# using the official WhatsApp API C#. This C# code uses HttpClient to make a simple API call to the WhatsApp Cloud API C#. This demonstrates WhatsApp API integration C# best practices.

Create a file named SendMessage.cs and add the following code.

To run this script:

Replace YOUR_API_TOKEN and RECIPIENT_NUMBER with your details.

Create a console project and run: dotnet run.

You've just successfully sent an automated WhatsApp message using C#! This simple function demonstrates how to send WhatsApp message C# and is the foundation for all outbound messaging using the WhatsApp API C#. This C# code to send WhatsApp message can be easily integrated into your C# application or Windows application.

Part 2: Receiving Messages with a C# Webhook

To build a WhatsApp bot, your application needs to listen for incoming messages. The WhatsApp API C# does this using webhooks. When a user messages your number, WhatsApp sends the message data as a JSON POST request to a URL you specify.

We'll use ASP.NET Core, the modern .NET web framework, to create a simple webhook server. This demonstrates WhatsApp API integration C# and how to receive messages using WhatsApp API integration in C#.

1. Create a Webhook Controller (Controllers/WhatsAppWebhookController.cs):

2. Update Program.cs or Startup.cs (for .NET 6+):

To make this work:

Run the ASP.NET Core App: dotnet run. Your server is now running on localhost:5000 (or the port specified in launchSettings.json).

Expose to the Web: WhatsApp can't reach localhost. Use a tool like ngrok to create a public URL for your local server:

Configure the Webhook: Copy the https://....ngrok.io URL provided by ngrok, append your route (/webhooks/whatsapp), and paste it into the Webhook URL field in your SendZen dashboard.

Now, when you send a message to your WhatsApp number, you'll see the message data printed in your console.

Part 3: Building a Complete WhatsApp Bot in C#

Let's combine what we've learned to create a simple but complete WhatsApp bot. This bot will reply to specific keywords, demonstrating a full WhatsApp bot API C# implementation.

We'll modify our controller to include the SendWhatsAppMessageAsync function. This example shows how to create WhatsApp bot C# from scratch using WhatsApp API integration C#.

Add to appsettings.json:

{
  "SendZen": {
    "ApiToken": "YOUR_API_TOKEN"
  }
}

Run this updated ASP.NET Core application with ngrok again. Now, when you send "hello" or "status" to your WhatsApp number, the bot will reply automatically! This is the foundation for all WhatsApp automation with C# and demonstrates how to send WhatsApp message using C# programmatically.

This implementation uses the WhatsApp Cloud API C# for reliable messaging and shows WhatsApp API integration in C# best practices. You can extend this to create a full Chatbot WhatsApp C# system.

Advanced Topics & Best Practices

Scaling Up: C# WhatsApp Bulk Sender

To send bulk messages programmatically, such as alerts to all your users, simply loop through a list of recipient numbers and call the SendWhatsAppMessageAsync function for each. Use Task.WhenAll for parallel processing. This demonstrates how to send WhatsApp message programmatically C# at scale using WhatsApp API integration C#.

Important: To initiate conversations with users, WhatsApp requires you to use pre-approved Message Templates. This is a crucial policy to prevent spam. You can easily manage and send templates via the SendZen API. For bulk campaigns, use templates.

ASP.NET Core WhatsApp API Integration

For a more robust ASP.NET Core implementation, create a service class to separate concerns and use dependency injection. This demonstrates WhatsApp API integration C# with ASP.NET Core and shows WhatsApp business API integration C# best practices. This is perfect for ASP.NET Core send WhatsApp message implementations.

1. Create a Service Interface (Services/IWhatsAppService.cs):

2. Create a Service Implementation (Services/WhatsAppService.cs):

3. Register the Service (Program.cs):

4. Update Controller to Use Service:

Using HttpClientFactory (Recommended)

For production applications, use IHttpClientFactory to properly manage HttpClient instances:

Webhook Security

Add webhook signature validation for production:

Twilio WhatsApp C# Alternative

While this guide focuses on SendZen's WhatsApp API C# integration, some developers also use Twilio WhatsApp C#, Twilio WhatsApp API C#, or Twilio send WhatsApp message C#. However, SendZen provides a more streamlined C# WhatsApp API experience with better WhatsApp API integration C# features and doesn't require Twilio C# WhatsApp setup.

Send WhatsApp Message from ASP.NET C#

For ASP.NET Core send WhatsApp message functionality, use the service pattern demonstrated in this guide. This enables send WhatsApp message from ASP.NET C# and send WhatsApp message using ASP.NET C# capabilities in your web applications.

Send WhatsApp Message from Windows Application C#

You can also use this code in Windows Forms or WPF applications. This allows you to send WhatsApp message from Windows application in C# and send WhatsApp message from C# code project directly from desktop applications.

Additional Resources

WhatsApp API C# GitHub Examples

Looking for more examples? Check out WhatsApp API C# GitHub or WhatsApp API GitHub C# repositories for additional code samples, integrations, and community contributions. Our implementation demonstrates how to use the WhatsApp Cloud API C# effectively.

Key Features Covered

✅ Send WhatsApp message C# - Complete API integration

✅ WhatsApp API send message C# - Production-ready code

✅ C# send WhatsApp message - Simple and reliable

✅ WhatsApp bot API C# - Full bot implementation

✅ WhatsApp Business API C# - Enterprise-ready solution

✅ WhatsApp API integration C# - Best practices included

✅ WhatsApp API integration in C# - Framework integrations

✅ Chatbot WhatsApp C# - AI-powered bot examples

Common Questions

Q: How do I send WhatsApp message using C#?
A: Use the SendWhatsAppMessageAsync function provided in Part 1. It uses C#'s HttpClient to send messages via the WhatsApp API C#.

Q: How to integrate WhatsApp API in C#?
A: Follow Part 1 to integrate WhatsApp API in C#. The code examples demonstrate WhatsApp API integration in C# best practices.

Q: How do I send WhatsApp message C#?
A: Use the SendWhatsAppMessageAsync method to send WhatsApp message C#. See Part 1 for complete examples.

Q: Can I send WhatsApp message from C#?
A: Yes, you can send WhatsApp message from C# using the code examples in Part 1. For development, you can send WhatsApp message C# free.

Q: How to send WhatsApp message programmatically C#?
A: Use the code examples in Part 1 to send WhatsApp message programmatically C#. The function uses HttpClient to make HTTP requests to the WhatsApp API C#.

Q: Is there WhatsApp API C# example code?
A: Yes, this entire guide provides WhatsApp API C# example code that you can use directly in your C# projects.

Q: How to send WhatsApp message using C#?
A: Use the SendWhatsAppMessageAsync function in Part 1 to send WhatsApp message using C#. It handles all API communication for you.

Q: Can I use Twilio WhatsApp C# instead?
A: While you can use Twilio WhatsApp C#, Twilio WhatsApp API C#, or Twilio send WhatsApp message C#, SendZen provides a more streamlined C# WhatsApp API experience.

Q: How to send WhatsApp message from ASP.NET C#?
A: Use the ASP.NET Core examples in the Advanced Topics section to send WhatsApp message from ASP.NET C# and send WhatsApp message using ASP.NET C#.

Q: How do I send WhatsApp message from Windows application in C#?
A: Use the code examples in Part 1 to send WhatsApp message from Windows application in C#. They work in both console and Windows Forms/WPF applications.

Q: Is there WhatsApp API C# free?
A: Yes, you can use the WhatsApp API C# free tier during development. For production, use the official WhatsApp Business API C#.

Q: How to send WhatsApp message from C# code project?
A: Use the SendWhatsAppMessageAsync function to send WhatsApp message from C# code project. See Part 1 for complete examples.

Q: Can I send WhatsApp message C# free?
A: Yes, you can send WhatsApp message C# free during development. The C# send WhatsApp message free tier allows testing before production deployment.

Q: How to send WhatsApp message using WhatsApp API C#?
A: Use the SendWhatsAppMessageAsync function to send WhatsApp message using WhatsApp API C#. It demonstrates send message using WhatsApp API C# best practices.

Q: Is there WhatsApp API C# GitHub repository?
A: Yes, check out WhatsApp API C# GitHub repositories for community examples and contributions.

Q: How to use WhatsApp Business API for C#?
A: Follow this guide to use the WhatsApp Business API C#. All examples demonstrate WhatsApp business API integration C# best practices.

Q: How do I send message to WhatsApp using C#?
A: Use the SendWhatsAppMessageAsync function to send message to WhatsApp using C#. See Part 1 for complete examples.

Q: Can I create a WhatsApp bot C#?
A: Yes! Follow Part 3 to create WhatsApp bot C#. It shows you how to build a complete Chatbot WhatsApp C#.

Q: How to send WhatsApp message in C#?
A: Use the examples in Part 1 to send WhatsApp message in C#. The code shows how to send WhatsApp message C# using the official API.

Q: How do I send WhatsApp message through C#?
A: Use the SendWhatsAppMessageAsync function to send WhatsApp message through C#. It handles all the API communication for you.

Q: Is there WhatsApp SDK C#?
A: While there's no official WhatsApp SDK C#, this guide shows you how to integrate the WhatsApp API for C# directly using HttpClient.

Q: How to send WhatsApp message C# example?
A: See Part 1 for complete send WhatsApp message C# example code that you can use directly in your projects.

Q: Can I use WhatsApp API in C#?
A: Yes, follow Part 1 to use WhatsApp API in C#. The guide covers WhatsApp API in C# step by step.

Q: How to send message on WhatsApp using C#?
A: Use the SendWhatsAppMessageAsync function to send message on WhatsApp using C#. See Part 1 for complete examples.

Q: How do I send WhatsApp message using C# free?
A: Use the send WhatsApp message using C# free examples in Part 1. They demonstrate how to send WhatsApp message C# free during development.

Q: Can I send WhatsApp message from ASP.NET C#?
A: Yes, use the ASP.NET Core examples in the Advanced Topics section to send WhatsApp message from ASP.NET C#.

Q: How to use WhatsApp API net C#?
A: Follow Part 1 to use WhatsApp API net C#. The guide shows WhatsApp API net C# integration using .NET HttpClient.

Q: Is there WhatsApp API documentation C#?
A: Yes, check the WhatsApp API documentation C# sections throughout this guide for detailed explanations and examples.

Q: How do I send WhatsApp message using Twilio C#?
A: While you can send WhatsApp message Twilio C#, SendZen provides a simpler alternative with send WhatsApp message using Twilio C# functionality built-in.

Q: Can I send WhatsApp message from Windows application in C#?
A: Yes, use the code examples in Part 1 to send WhatsApp message from Windows application in C#. They work in Windows Forms, WPF, and console applications.

Start Building Now

You now have a complete toolkit for WhatsApp API programming in C# .NET. By combining a simple function to send WhatsApp message using C# and an ASP.NET Core webhook to receive them, you can build powerful, automated communication workflows.

Whether you're building a Chatbot WhatsApp C#, integrating the WhatsApp API C# into your application, setting up WhatsApp API integration C#, or creating a C# send WhatsApp message system, SendZen makes it simple.

With SendZen's developer-first WhatsApp API C# solution, you can stop wrestling with complex setups and focus on creating amazing applications. Use this guide to integrate WhatsApp API in C#, send WhatsApp message programmatically C#, and build robust WhatsApp API integration C# solutions.

WhatsApp API with C# .NET

Prerequisites#

Part 1: How to Send a WhatsApp Message with C##

Part 2: Receiving Messages with a C# Webhook#

Part 3: Building a Complete WhatsApp Bot in C##

Advanced Topics & Best Practices#

Scaling Up: C# WhatsApp Bulk Sender#

ASP.NET Core WhatsApp API Integration#

Using HttpClientFactory (Recommended)#

Webhook Security#

Twilio WhatsApp C# Alternative#

Send WhatsApp Message from ASP.NET C##

Send WhatsApp Message from Windows Application C##

Additional Resources#

WhatsApp API C# GitHub Examples#

Key Features Covered#

Common Questions#

Start Building Now#