Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Imgix is a visual media platform for managing, processing, rendering, optimising and delivering your existing images.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
Typekit is an online service which offers a subscription library of fonts.