Express is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
WhatsApp Business is a free to download app available on Android and iPhone using which businesses can connect with their customers.