Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Google Analytics is a free web analytics service that tracks and reports website traffic.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Klaviyo is an email marketing platform for online businesses.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.