A product catalog is required whenever you need to transfer prices (offer catalogue) or product data (respective product catalogue) to Amazon – for example, when creating a new offer (offer catalogue) for an item that already exists in the Amazon catalog or when updating product information such as titles, descriptions, or images.

No catalog is needed if you're only sending inventory data (stock levels) for products that are already listed on Amazon. The stocks are updated separately. As before, the stock update is based on the Amazon default settings, price or product details remain unchanged.

In summary:

• ✅ Catalog required when: transferring prices or product data, creating a new offer

• ❌ No catalog required when: only updating inventory