The setup
A reseller running 7 eBay accounts across two warehouses. Inventory was tracked in a spreadsheet that had grown 14 sheets and counting; "what's listed where" required asking three different employees.
What we shipped
A unified dashboard backed by the eBay Inventory and Trading APIs. Single search across all accounts, listing-level analytics (impressions / watchers / sell-through), and a bulk relist tool that handles the eBay rate limits without manual babysitting.
We added a low-stock alert that pings Slack when SKU count drops below the per-listing reorder point.
Outcome
Listing throughput up roughly 2.1× because the bulk tool replaced what was a 4-hour manual job per warehouse per week. Stockouts dropped to near-zero. The spreadsheet died.