Google Analytics is a free web analytics service that tracks and reports website traffic.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
Hotjar is a suite of analytic tools to assist in the gathering of qualitative data, providing feedback through tools such as heatmaps, session recordings, and surveys.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.