FMCG POS & Inventory Platform
Offline-first point-of-sale and real-time inventory synchronization platform for wholesale and retail SMEs
Problem
Fast-moving consumer goods (FMCG) retailers and wholesalers across Nigeria rely on disconnected, error-prone tools like paper notebooks, basic calculators, and standalone Excel sheets. Sales transactions are not linked to stock levels in real-time, resulting in severe stockouts, untracked shrinkage, and inaccurate financial reporting. Furthermore, frequent internet outages and unstable power grids mean cloud-only POS software completely paralyzes business operations the moment the network drops.
Solution
Architecting and building a resilient, offline-first point-of-sale and inventory management platform specifically engineered for low-connectivity retail environments. Native Flutter tablet applications allow store clerks to process high-speed checkouts seamlessly offline, while a robust Spring Boot backend reconciles local transactions with cloud databases immediately upon network restoration.
How It Was Built (Architecture & Implementation)
Offline-First Mobile Architecture (Flutter & Hive/SQLite)
Designed native Flutter POS client applications optimized for high-speed tablet operation. Integrated local high-speed NoSQL caching (Hive) and structured relational storage (SQLite) so every product lookup, barcode scan, and sales transaction occurs with zero network latency and 100% offline uptime.
Core Backend & Sync Engine (Java & Spring Boot)
Architected the central transactional backend using Spring Boot and PostgreSQL. Developed deterministic synchronization algorithms capable of receiving batched offline transactions, reconciling inventory deltas, and handling timestamp ordering conflicts without double-counting inventory or revenue.
Multi-Store Inventory & Reordering Intelligence
Engineered multi-warehouse stock allocation tracking, automated re-order level triggers based on historical sales velocity, and detailed daily profit margins breakdown reports for store proprietors.
Resilient Network State Handling
Built background sync workers with exponential backoff and delta-based payloads. Only modified records are transmitted over cellular networks, minimizing bandwidth consumption and data costs for retail shop owners.
How I Improved It Over Time (Evolution & Iteration)
[ Phase 1 (Core POS & Offline Storage Engine) ]
Developed the foundational Flutter tablet application with local Hive database persistence, enabling instantaneous product search, cart assembly, and offline receipt generation for high-volume retail checkouts.
[ Phase 2 (Cloud Reconciler & Conflict Resolution Architecture) ]
Built the Spring Boot cloud synchronization gateway. Solved the critical distributed systems challenge of multi-register concurrency—ensuring that when multiple offline tablets sync simultaneously, stock levels decrement accurately without race conditions.
[ Phase 3 (Enterprise Analytics & Multi-Store Dashboard — Current Focus) ]
Currently expanding the web-based managerial dashboard with real-time sales analytics, low-stock notifications, and staff performance metrics ahead of Q4 2026 production deployment.
Outcome & Business Impact
In active development (Expected production deployment Q4 2026). Solving one of the hardest problems in emerging market retail tech: building reliable, high-speed transactional software that survives network dropouts while maintaining strict data integrity and real-time cloud visibility.
My Role & Execution
Sole Lead Full-Stack Architect. Designing the Spring Boot backend microservices, building the native Flutter cross-platform tablet client, engineering the offline-to-cloud synchronization state machine, and managing cloud database infrastructure.
Key Learnings
- Solving complex distributed systems synchronization, idempotency, and conflict resolution in offline-first mobile apps
- Optimizing native mobile UX and database read/write speeds for fast-paced, high-volume retail checkout counters
- Designing resilient Spring Boot APIs tailored to handle intermittent, high-latency cellular network connections