Websites that have a shopping cart or checkout page, either using a known ecommerce platform or a custom solution.
cdnjs is a free distributed JS library delivery service.
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.
OpenResty is a web platform based on nginx which can run Lua scripts using its LuaJIT engine.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.