Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
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.
Open Graph is a protocol that is used to integrate any web page into the social graph.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
Stripe offers online payment processing for internet businesses as well as fraud prevention, invoicing and subscription management.
Tilda is a web design tool.
WhatsApp Business is a free to download app available on Android and iPhone using which businesses can connect with their customers.