The Fuel Depot

A regional fuel-delivery operator was running orders, invoices, and account management across WhatsApp messages, paper slips, and three disconnected spreadsheets. Tracking a single delivery meant calling three people. Reconciliation took days.

A single mobile app for customers to order fuel, view invoices, and manage their accounts — backed by a clean API and one source of truth. Strong types end-to-end so a field change in the database surfaces as a TypeScript error in the mobile client at build time.

• ▸Expo / React Native mobile app with a polished ordering flow and account screens
• ▸Express 5 API documented with OpenAPI; clients generated via Orval into a shared package
• ▸PostgreSQL + Drizzle ORM with migrations and seed scripts
• ▸Monorepo with shared validation (Zod) and type-safe clients across all apps
• ▸Auth, roles, and tenant isolation at the API layer
• ▸Deployment scripts and environment templates handed over

The hardest part was not the AI or the code — it was getting the team to trust one number for stock on hand. Once the app became the single source of truth, the surrounding chaos collapsed on its own.