Shopify keeps one cost per inventory item. When you change it, the old value is replaced, so earlier margins stop matching. CostSonar records cost changes from its first check and keeps a dated history. It sorts your catalogue into variants selling below cost, variants with no cost set, and variants on a thin margin. Archived and draft products are skipped. Access is read-only. The app never writes to your store.

• See the variants selling below cost, biggest loss per unit first
• Get an email when a product that was making money starts losing it
• Keep a dated record of cost changes from your first check
• Find products with no cost set, which profit reports cannot include