Drupal is a free and open-source web content management framework.
Firebase is a Google-backed application development software that enables developers to develop iOS, Android and Web apps.
Google Publisher Tag (GPT) is an ad tagging library for Google Ad Manager which is used to dynamically build ad requests.
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.