01 · The challenge
Small retail businesses had no affordable, purpose-built tool to manage inventory, orders and clients in real time and produce tax-compliant invoices - most relied on paper or generic spreadsheets.
02 · What I built
A complete multi-tenant SaaS - backend and dashboard - for managing orders, live inventory and client histories, with one-click tax-compliant invoice printing built in.
03 · The hard part
Two correctness problems. Multi-tenancy is enforced structurally at the data layer, so one business can never see another's data. And stock reconciliation on order edits uses atomic database operations and delta calculation to prevent the double-deduction bugs a naive approach produces.
04 · The outcome
One deployment serves many isolated businesses safely. Real-time stock validation blocks overselling. Tax-compliant invoicing with no third-party accounting software.
05 · Stack