Amoonis Boutique

Real e-commerce is unforgiving in two places at once: money and operations. Checkout has to take payments across mobile and web without ever overselling stock, double-charging a customer, or losing an order to a dropped payment callback. At the same time the boutique's team needed to run the whole business — products, orders, promos, regions, analytics — without every staff member having full admin power. And it all had to work in two languages (EN/AR, RTL) across two regions, served to both a Flutter app and a web client from one codebase.

I built the backend as a layered Express API (routes → controllers → services) and made payment correctness the centerpiece. Every payment is re-verified server-side with the gateway (the client is never trusted); the PAID flip is an idempotent, conditional update so a callback, webhook, reconciliation job and retries all converge on exactly one order placement; stock is reserved with a row-conditional atomic decrement that closes the oversell race; and Apple Pay's non-idempotent execute is protected by an atomic single-winner claim. A reconciliation cron recovers stranded payments and an expiry cron restores stock and promo usage. On top of that I built a 10-permission manager RBAC (admins delegate scoped access, enforced in middleware and mirrored across the admin UI in three layers), FCM push with per-user preferences and an inbox, a pg-boss job system on Postgres (no Redis), Bunny CDN image delivery, multi-region catalog visibility, promo codes, and an auto-translating EN/AR content layer. The Next.js admin + storefront is feature-sliced with React Query + Redux Toolkit and react-hook-form + Zod throughout.