Varnish is a reverse caching proxy.

PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.

Cloudflare is a web-infrastructure and website-security company, providing content-delivery-network services, DDoS mitigation, Internet security, and distributed domain-name-server services.

Apache is a free and open-source cross-platform web server software.

Unix is a family of multitasking, multiuser computer operating systems.

OpenSSL is a software library for applications that secure communications over computer networks against eavesdropping or need to identify the party at the other end.

Mod_fcgid is a high performance alternative to mod_cgi or mod_cgid, which starts a sufficient number instances of the CGI program to handle concurrent requests, and these programs remain running to handle further incoming requests.

PHP is a general-purpose scripting language used for web development.

Google Analytics is a free web analytics service that tracks and reports website traffic.

Amazon Application Load Balancer (ALB) distributes incoming application traffic to increase availability and support content-based routing.

Amazon Web Services (AWS) is a comprehensive cloud services platform offering compute power, database storage, content delivery and other functionality.

ASP.NET is an open-source, server-side web-application framework designed for web development to produce dynamic web pages.

Azure Front Door is a scalable and secure entry point for fast delivery of your global web applications.

Azure is a cloud computing service for building, testing, deploying, and managing applications and services through Microsoft-managed data centers.

Windows Server is a brand name for a group of server operating systems.

Internet Information Services (IIS) is an extensible web server software created by Microsoft for use with the Windows NT family.

Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.

Envoy is an open-source edge and service proxy, designed for cloud-native applications.