How I built a fully custom e-commerce from scratch using Firebase Realtime Database and Netlify — no off-the-shelf platforms: per-product pricing variants, an admin panel protected by a PBKDF2 hash with no password in the source code, duplicate-proof atomic order numbering, and automatic vendor identification via a cross-app token.
The context
A POS terminal reseller needed a showcase site with an integrated e-commerce. The requirements were clear: no payment gateway to integrate (checkout with ready-made payment links or bank transfer details), a catalog of around seven products with selectable pricing variants, and the ability for their sales team to place orders directly from the site — with the salesperson’s name automatically saved on each order, read from their identity already authenticated in the internal management panel.
The decision to skip off-the-shelf e-commerce platforms was deliberate: something fully custom was needed, integrable with the Firebase ecosystem already in use for the management panel, and controllable in every detail. Resulting stack: vanilla HTML/CSS/JS, Firebase Realtime Database for catalog and orders, Firebase Storage for images and PDFs, Netlify for hosting and serverless functions.
