Loppis!
Uses the latest and greatest VanillaJS v1.0. Build using old school jQuery and plain html to act as a reminder to what modern tools as React, Webpack both add and solve in terms of complexity.
Built using Firebase so go here for docs https://firebase.google.com/docs/
https://github.com/firebase/functions-samples/tree/master/quickstarts/email-users
Email template taken from https://github.com/sparksuite/simple-html-invoice-template