Home › Guides › Metafield for maker's code

Storing the maker's code in Shopify

Short answer: Keep one maker's code per variant. Two places hold one code per variant whatever your export contains: a variant metafield, which you edit in the bulk editor but which does not appear in the product CSV, or a side sheet keyed by SKU. Shopify's sample files also show a Google Shopping MPN column, but our own test export on 25 September 2026 did not include it. Shopify's documentation says a defined product metafield appears in the CSV export; in Shopify's sample file its value sits only on the product's first row.

Steps for a variant metafield

1. Shopify admin → Settings → Custom data → Variants → Add definition. Name: "Manufacturer code". Namespace and key: custom.manufacturer_code. Type: single line text. Save.
2. Open each product → variant → scroll to Metafields → enter the maker's model or part number exactly as the supplier wrote it.
3. For many variants, use Shopify's bulk editor (Products → select → Bulk edit) and add the metafield column.
4. Variant metafields are not included in product CSV export or import; Shopify points to the variant bulk editor for editing them in bulk. To keep a copy you can check, use a simple side sheet: columns Variant SKU, Manufacturer code, Source.
5. To check the codes, add your code column to the CSV you load and choose it under "Match identifier columns" in the checker.

What appears in the product CSV

• Google Shopping MPN column: not always. Shopify's help page and sample files show it, but a real export from our own store on 25 September 2026 had no Google Shopping columns at all, even though the test products had MPN values. Open your own export and check the headers.
• Product metafield: included once defined, according to Shopify's documentation; in Shopify's sample file the value sits on the product's first row only. Check one multi-variant product in your own export before relying on it. It holds one value per product, so it suits only a product sold in one version.
• Variant metafield: no. Use the variant bulk editor or a side sheet.

The Commission guidance (section 3.5.3) says each identifier should point to exactly one product variant, so products sold in several sizes or colours usually need a code per variant.

Rules of thumb

• Enter the code exactly; do not "clean" it.
• Record where it came from (supplier sheet, packaging, email) in a second metafield or your side sheet.
• If the maker says one code covers every variant, record that answer and where it came from. The guidance expects one code per variant, so ask whether a per-variant code exists.

Check the export after you add the column — free

Questions