This is a billing and invoice tool written in EmberJS. It can create invoices, generate PDF documents from them, and process payments through the Stripe API.
PDF generation is done client side, in Javasript, using the excellent pdfkit library.
The app connects to a backend REST API built with rails. See: https://github.com/troygnichols/zark-billing-api
This is app is deployed to heroku: