mpn

MPN — Manufacturer Part Number — is the fallback identifier for the products that genuinely have no GTIN, and the precision identifier for industries where multiple sellers stock the same item from the same manufacturer. Electronics, automotive parts, industrial supplies, and replacement parts all live and die by MPN matching. In those verticals, GTIN alone often isn't enough because GTINs sometimes get reused across slightly different SKUs.

The format MPN takes depends on the manufacturer. Apple uses long descriptive strings (`iPhone-15-Pro-Max-256-Titanium`), Sony uses compact codes (`BO-WHX1000XM5`), and industrial parts often use cryptic supplier identifiers. The feed should preserve whatever the manufacturer assigned — don't normalise the format. Channels match against the manufacturer's actual MPN, not your idea of how it should look.

For own-brand products, MPN is your internal product code. Set brand to your store name, MPN to your code, and the GTIN/MPN pair acts as the unique identifier. Don't use bulk-fill placeholders like `Various` or `STORE-001` — they look like data quality problems to channels' classifiers and trigger broader account-level reviews.