Amazon S3 or Amazon Simple Storage Service is a service offered by Amazon Web Services (AWS) that provides object storage through a web service interface.
Drupal Multisite enables separate, independent sites to be served from a single codebase.
Drupal is a free and open-source web content management framework.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Mailchimp is a marketing automation platform and email marketing service.
Mautic is a free and open-source marketing automation tool for Content Management, Social Media, Email Marketing, and can be used for the integration of social networks, campaign management, forms, questionnaires, reports, etc.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Pantheon is a WebOps (Website Operations) and Management Platform for WordPress and Drupal.
Varnish is a reverse caching proxy.