Product Identifiers in Schema Markup: How GTIN, SKU, and MPN Determine AI Agent Visibility
Product identifiers like GTIN, SKU, and MPN in your structured data are the primary mechanism AI shopping agents use to match your products across stores, deduplicate listings, and surface the right offer in a recommendation. Without them, your products are name-matched at best and invisible at worst. When ChatGPT compares prices for “Sony WH-1000XM5 headphones,” it needs to know that the product on your store is the same Sony WH-1000XM5 on Amazon, Best Buy, and six other retailers. That matching happens through product identifiers encoded in schema markup, not through product titles or descriptions. If your Product schema lacks a GTIN, the agent cannot confidently link your listing to the canonical product, and you drop out of the comparison. ...