Shopify inventory CSV columns and supplier stock checks

What this guide explains

Understand Shopify inventory CSV matching before running an update workflow.

• The Shopify export should stay the base file because it already matches Shopify's expected inventory structure.
• Supplier files need a reliable SKU column and a current quantity column before they can update Shopify rows.
• Unmatched SKUs, duplicate SKUs, blank SKUs, and invalid quantities should be reviewed in a separate exception report.

Choose which file owns the structure

The Shopify export already carries the handles, locations, and column names expected by Shopify, so it should remain the structural source of truth. The supplier file contributes the current SKU-to-quantity values. Rebuilding the import around supplier headers can drop Shopify-specific fields or place a quantity in the wrong location column.

• Back up the original Shopify export before applying supplier values.
• Choose one supplier SKU column and one quantity column explicitly.
• Keep unmatched Shopify rows unchanged until their stock rule is decided.

Resolve exceptions before the inventory import

A duplicate supplier SKU can mean duplicate rows, multiple warehouses, or separate stock states. A blank supplier SKU cannot be matched safely, and a negative or non-numeric quantity needs a business rule. Keep these rows in the exception report rather than silently choosing one value.

• Confirm whether multiple warehouse quantities should be summed or kept separate.
• Do not interpret a missing supplier row as zero stock without an explicit policy.
• Re-open the ready CSV and verify row count, headers, location, and several known SKUs.

Sources and further reading

• Shopify Help Center: product inventory setup — Official inventory tracking and inventory CSV guidance.
• Shopify Help Center: CSV files — Official encoding, spreadsheet editing, and import guidance.