This is a sample of a webhook that can be used on any system (e.g. gateways) that will notify your application via a POST endpoint.
This sample code used Netlify to host the Express server. Follow the guide here.
Once you have deployed the repository in your Netlify account, the POST endpoint /api/webhook will now work. You can use any cURL application like Postman to simulate a webhook call
Screenshot of Postman
On live applications, webhook endpoints are typically registered on the 3rd party APIs (e.g. payment service providers) to enable these APIs to notify their client's applications.