Skills

gtin-identifier-auditor

Product feeds v2
@cartlift 133 installs updated 32d ago MIT license
README Versions Community (0)

GTIN identifier auditor

Wrong identifiers quietly cost reach: the item shows, but Google cannot match it to the catalog. This skill checks every identifier by rule, not by eye.

When to use

  • Before launching a new supplier's range in Shopping.
  • When Merchant Center reports "Limited performance due to missing identifiers" or "Invalid GTIN".

Input

Feed rows with id, item_group_id, brand, gtin, mpn, identifier_exists, condition, and title. Optional: the supplier's own identifier list.

Checks

  1. Format. GTIN must be numeric, length 8, 12, 13 or 14 (GTIN-8, UPC-A, EAN-13, ITF-14). Strip spaces and hyphens; a leading zero dropped by a spreadsheet turns a UPC into 11 digits, flag it.
  2. Check digit. From the right, excluding the check digit, weight digits 3,1,3,1…; check digit = (10 − sum mod 10) mod 10. Report failures with the computed digit.
  3. Reserved ranges. Prefixes 020–029, 040–049 and 200–299 are internal/restricted-circulation numbers and are rejected; 978/979 are ISBNs (valid for books only).
  4. Uniqueness. One GTIN on two different variants (other size or color) is an error. Same GTIN on duplicate rows is a feed duplication issue.
  5. Brand + MPN. When no GTIN exists, brand and mpn together are required for branded goods. Brand must not be the store name unless the store makes the product.
  6. identifier_exists. no only for custom, handmade, vintage or private-label items with no GTIN; no on an item that has a manufacturer GTIN gets it disapproved.

Rules

  • Never generate, look up by guess or "correct" a GTIN. A failed check digit is reported with the computed digit as a hint, not written into the feed.
  • Rows where brand or product origin is unknown go to "needs owner input".
  • Read-only; the output is a fix list for a human.

Output format

| id | gtin | issue | suggestion |
| SKU-1182 | 5901234123458 | ok | |
| SKU-1183 | 590123412345 | 12 digits, check digit fails | verify with supplier |
| SKU-2210 | 0012345000065 | same GTIN as SKU-2209 (other size) | supplier sheet needed |
| SKU-3301 | — | identifier_exists=no but brand "Salomon" | find manufacturer GTIN |
Summary: 1 240 rows, 1 102 ok, 61 invalid, 77 missing; 14 need owner input.

License

MIT