Few words on technology used
The Friendly Pix frontend is built using JavaScript, Firebase and jQuery.
Friendly Pix is written in ES2017 using Modules so for wide browser support the code is packed and transpiled to ES5 using Webpack.
The Auth flow is using Firebase-UI.
Javascript Runtime dependencies as well as Build and deploy dependecies are managed using npm.
Server-side micro-services are built on Cloud Functions for Firebase.