Introduction
Webhooks are a critical component of modern web development, enabling seamless communication between different applications and services. They facilitate real-time data exchange and event notification, making them invaluable for various use cases, such as integrating third-party services, triggering actions based on specific events, and keeping multiple systems in sync. In this comprehensive guide, we'll walk through the process of creating a POST webhook URL in an ASP.NET Core Web API, covering everything from setup to implementation and testing.
Table of Contents
- Setting Up the ASP.NET Core Web API Project
- Creating the Post Webhook
- Implementing Webhook Handling Logic
Setting Up the ASP.NET Core Web API Project
Before we dive into creating the webhook functionality, let's set up the ASP.NET Core Web API project.
- Open Visual Studio 2022.
- Click on "Create a new project."
- Select "ASP.NET Core Empty Project."
- Provide a name and location for your project, and click "Create."
- Now select Framework ".NET 8.0".
- Click "Create" to generate the project structure.
Creating the Post Webhook
Now, we will start creating the post webhook in the project created above. First, we will add two more files; one is an interface, and the other is a repo class for the logical calculation, as given in the below image.

As you can see above, we have created two new files, IWebHookRepo and WebHookRepo.
Now, we need to modify the Program.cs file as given below.
using WebHookDemo;
var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
app.MapGet("/", () => "Hello World!");
//Listen for POST webhooks
app.MapPost("/webhook", async (HttpContext context, IWebHookRepo receiveWebook) =>
{
using StreamReader stream = new StreamReader(context.Request.Body);
return await receiveWebook.UpdateTransactionStatus(await stream.ReadToEndAsync(), context);
});
app.Run();
In the above code, we've defined an endpoint /webhook that listens for HTTP POST requests. When a request is received, the UpdateTransactionMethod action method is invoked, which will send the request to the repo class. You can customize this method to handle the webhook payload according to your application's requirements. We are calling a method UpdateTransactionStatus which is in the IWebHook interface. Now, we will see the method in the interface.

Michael ClintonPosted Nov 23, 2024, 6:43 PM
So, do I check for a header API in the program.cs ?
Glenn WilliamsPosted Oct 18, 2024, 4:50 PM
No matter what payload I enter I receive an error. Can you provide a sample json string? https://i.imgur.com/jdVWoCE.png
sPosted Sep 26, 2024, 7:58 AM
Alot of information was skipped
sPosted Sep 26, 2024, 7:58 AM
The example is not useful.