Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
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.
Klaviyo is an email marketing platform for online businesses.
LiteSpeed is a high-scalability web server.
Open Graph is a protocol that is used to integrate any web page into the social graph.
PHP is a general-purpose scripting language used for web development.
Shopware is an enterprise-level ecommerce platform.
A modest JavaScript framework for the HTML you already have.