I built a full POS system — for a real business, not a tutorial. My relative was running their store with pen and paper. I fixed that. What it does: → Product catalog + barcode scanning → Sales & stock tracking → Real-time charts & low stock alerts → Cloud sync via Supabase → Excel/JSON backup → Mobile-first UI Built with: HTML, CSS, JS, Supabase, Chart.js, SheetJS. The real lessons: → Clean UI is a feature → Real users beat GitHub stars Need solutions that actually work? Let's talk. ~600 characters. Want any tweaks?