Multi-Business POS — La Brocha System

The problem

La Brocha, a hardware store with multiple sales points, operated with disconnected inventory and sales processes. The client needed a POS system that worked on both web and mobile devices, supported multiple business units under the same installation, and provided real-time metrics dashboards for day-to-day operational decisions.

The solution

I designed a multi-tenant POS + CRM system: a FastAPI backend with PostgreSQL orchestrated via Docker Compose, a React 19 + Vite + TailwindCSS frontend, and Capacitor wrappers for Android and iOS. An Electron wrapper was added for desktop use.

The form layer uses react-hook-form + Zod for typed client-side validation that mirrors the Pydantic validation on the backend. Zustand manages global cart and session state. The metrics dashboard exposes sales, inventory, and margin KPIs in real time.

My role

I was the architect and lead developer. I defined the database schema (multi-tenant with negocio_id isolation), implemented the FastAPI endpoints, built the main frontend modules (POS, inventory, customers, reports), and configured Docker Compose for both development and production environments.

Outcome

The system centralizes La Brocha’s operations: sales, inventory, and customer management in a single platform. The Capacitor wrapper allows sales staff to use Android tablets as POS terminals without a native app. The metrics dashboard reduces report generation from hours to seconds.

Notable learning

React 19 with concurrent mode and Suspense requires a shift in thinking about async state. The cleanest pattern I found was using useSuspenseQuery from TanStack Query — the component declaratively “suspends” while data loads, eliminating manual loading state management and making the component logic simpler and more predictable.