Set a minimum stock level for each product variant at each location, or apply rules by collection. When online stock drops to that number, the add-to-cart button is blocked so the last units stay reserved for in-store customers, wholesale orders, or as a buffer against inventory sync delays. Get email alerts before you run out, either instantly or as a daily, weekly, or monthly report. The customer-facing message is fully editable. 5-minute setup, no code, no theme edits.