Backdrop is an open-source content management system (CMS) derived from Drupal 7, offering a user-friendly interface, customisable content types, taxonomies, views, theming capabilities, extensibility through modules, and regular security updates.
Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
Mailchimp is a marketing automation platform and email marketing service.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
PHP is a general-purpose scripting language used for web development.