JL Vendas is a system built to measure for my parents' clothing stores. Before it, sales control was done on paper and spreadsheets: writing down what each employee sold, adding it up by hand to know the revenue, checking the cash register at the end of the day, and calculating goals and bonuses manually. The system replaced that routine: each sale is registered in seconds with employee, amount, and payment method; the daily total and the employee ranking update instantly; goals and bonuses are calculated automatically; and the cash register for in-cash sales always stays balanced. It is a multi-store and multi-company system, and the owner follows every store from the phone through an installable PWA, with a consolidated overview and the ability to filter a single store. Each store has screens for sales, employees, calendar, dashboard, history, audit trail, calculator, price tag printing, and settings. The audit trail records everything that changed: created, voided, and deleted sales, cash adjustments, and configuration changes, with author and date. Business rules are built into the system: automatic goal calculation per employee per day, a manual bonus per sale, and the distinction between voiding a sale (which stays in the history with a reason) and deleting it, always correcting the cash register in both cases. On the technical side, it runs on React 19 with Vite and Tailwind, uses Firebase Firestore and Auth with no server of its own, and relies on pre-calculated monthly summaries plus a local IndexedDB cache to cut read costs and work offline. Isolation between companies is enforced by Firestore Rules. It runs in production today at the family stores with real sales data every day, and the next step is turning it into a product sold to other retail stores, with self-service onboarding, per-employee login, server-side validation through Cloud Functions, and subscription management.

• Online SystemSystem in production, available only to the stores.
• PlatformsWindows/macOS/Linux/iOS/Android (PWA)
• StacksReact 19, Vite, Tailwind CSS, Recharts, Firebase (Firestore/Auth), Vercel