Apache is a free and open-source cross-platform web server software.
Drupal is a free and open-source web content management framework.
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.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.
Stripe offers online payment processing for internet businesses as well as fraud prevention, invoicing and subscription management.