Apache is a free and open-source cross-platform web server software.
Calendly is an app for scheduling appointments, meetings, and events.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Freshchat is a cloud-hosted live messaging and engagement application.
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.
PHP is a general-purpose scripting language used for web development.