Multi-warehouse inventory management starts with a single system of record. Whether you use a dedicated WMS, a multi-channel platform, or a spreadsheet, all locations must update the same inventory pool in near-real-time.
Define which warehouse fulfills which channel. Having clear fulfillment routing rules prevents situations where two warehouses fulfill the same order or where the wrong warehouse ships an order that another location should handle.
Conduct monthly reconciliations between your system of record and each warehouse's physical count. Discrepancies caught monthly are manageable. Discrepancies discovered quarterly can mean weeks of overselling or phantom inventory.
When scaling to multiple warehouses, add locations incrementally — one warehouse at a time. Adding three locations simultaneously creates reconciliation complexity that overwhelms most inventory systems.