This 6-part tutorial shows how to build web applications with plain JavaScript and Firebase, not using any (third-party) framework or library. A JavaScript and Firebase application runs on the cloud, on a Node.js hosting environment on the Google Cloud Platform, and can be executed on any kind of computer device (smartphone, tablet or notebook). Unlike a front-end web application, a JS and Firebase web app may be a multi-user application shared with other users using Firebase Authentication, as is shown in the tutorials.