Multi-Warehouse Inventory Synchronization System
Inventory counts diverged across 4 warehouses, causing 25% overselling and stockout issues
Context
E-commerce retailer operating 4 warehouses in different regions. Selling 12,000 SKUs across online store, Amazon, eBay, and B2B channels. Each warehouse maintained separate inventory system with manual counts updated daily. When order came in, system checked nearest warehouse—if out of stock, order failed rather than checking other warehouses. Inventory synchronization happened once daily via Excel file export/import between warehouses. During peak season, inventory counts diverged significantly—same SKU showed different quantities across warehouses. Result: 25% of orders failed due to overselling, customers received cancellation notices after payment processed.
The Real Problem
Inventory systems at each warehouse were isolated—no real-time visibility into other warehouse stock levels. Manual synchronization process was error-prone: Excel files corrupted, sync failed silently, staff forgot to run sync process. Time lag: inventory changes in Warehouse A took 24 hours to appear in Warehouse B's system. Order routing logic was static—always checked nearest warehouse first, didn't consider stock availability across network. During high-volume periods, inventory counts became inaccurate due to timing: order processed at Warehouse A while sync file showed old count at Warehouse B. No single source of truth—each warehouse system was authoritative for its own location, but no unified view. Off-the-shelf inventory platforms assumed single warehouse or required expensive multi-location licenses. Data quality issues: product codes inconsistent across warehouses, units of measure different (cases vs. individual items), some warehouses counted damaged goods, others didn't.