Testing Webhooks with webhook.site

What is a Webhook?

Typically, requests are sent from a client to a server, and the server responds back to the client. (Request-Response structure)

Webhooks are generally used to notify of user actions that occur irregularly, such as when a user signs up on a website in a microservices architecture where notification and user management servers are separated, which triggers a signup confirmation email.

graph TD;
    User -->|Signup| MemberServer;
    MemberServer -->|Signup Webhook| MailServer;

In reality, it’s not a very large function; it’s not much different from a typical request. You just need to know that when a specific event occurs on the server, it sends a request to a particular server or client.

How to Test Webhooks

So, how can we test webhooks?

1. Wait for Completion

For example, if you have both a member server and a mail server, you can easily test by implementing everything and trying a signup.

However, a downside is that if there are multiple team members, each implementing the server functionalities, you will have to wait for the implementation of all functions to test a single webhook.

2. Implement a Dummy Server

Alternatively, you could implement a dummy server yourself.

Since the goal is to receive requests, you can create a server with a specific endpoint (assuming a mail server) that only needs to send a request upon a successful signup.

It could look something like this:

package main

import (
    "fmt"
    "net/http"
)

func main () {
    http.HandleFunc("/webhook", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintln(w, "Webhook received!")
    })

    http.ListenAndServe(":8080", nil)
}

You would implement the server this way and send a request to /webhook upon registration.

However, this method is not particularly recommended since it can be cumbersome to create, and every time a new function is required, you need to add a corresponding endpoint.

3. Use webhook.site

There is a site that you can use in such cases, which is webhook.site.

This site receives requests and allows you to verify how the response was received.

You can think of it as a dummy server that receives all requests.

Since it’s named webhook.site, it was inherently created to test webhook functionalities.

Upon visiting the site, a webhook URL unique to you is generated in the Your unique URL section.

Now, you just need to send requests to that URL. In my case, I sent a request using curl:

curl -X POST https://webhook.site/f5fcf7e6-2233-4374-8c73-32195b38e7fb -H "Content-Type: application/json" -d '{"name":"test"}'

Then you can see all the details about the request, including what request came in, what the body contained, what headers were included, etc.