1. Pull current inventory. From NetSuite or your ERP. On-hand by SKU, by warehouse, with reservations excluded.
2. Pull sales velocity. From Shopify, your WMS, or a sales feed. Units sold per SKU over the chosen lookback window.
3. Standardize the SKU. Trim, uppercase, strip prefixes, map between code systems so velocity and inventory line up.
4. Calculate days on hand. On-hand divided by daily velocity, with seasonality smoothing if the planner asks for it.
5. Apply your bands. Slow-mover threshold, target range, at-risk-of-stockout threshold. Different bands per category if needed.
6. Output the report. Full table for the record, flagged-only view for merchandising, and a Slack alert when a SKU crosses a threshold.