Feed optimisation for Google, ChatGPT and marketplaces

Price comparison sites and marketplaces such as idealo, Kaufland or OTTO expect their own feeds with their own required fields, categories and formats. The basis, however, is the same product data as for Google. We check your feeds for these channels to see whether they are compliant and whether all useful attributes are present.

• Requirements per channel: we compare your feed with the specifications of each site or marketplace and show which fields are missing or filled in incorrectly.
• A shared data basis: ideally, we add missing details such as GTIN, brand, variants or unit price at the source so that all channels benefit.
• Your feed tool: we work with your existing feed tool, together with you or your service provider.

Our focus is on the quality and completeness of your product data.

• Checking feed and website together: Google names missing return policies, insufficient contact information and misrepresentation as common reasons for account suspensions, in other words mainly details on the website. That is why we check feed and shop together, including technical SEO and structured data.
• Directly in Merchant Center: we implement many corrections with supplemental data sources and attribute rules, without you needing another tool. If you already have a feed tool, we work with it.
• Ready for AI surfaces: we link conversational attributes, product highlights and technical details with our work on visibility in AI answers in GEO.
• Our own tool for ChatGPT: we create the ChatGPT product feed with the Rheinwunder Feed Manager, which we developed ourselves.
• Tracking as the basis: if you wish, we derive custom labels from your Google Analytics 4 data, for example by sell-through or performance.
• Product texts with AI and editors: our AI product text generator creates titles and descriptions from your original texts and facts, and our editors check them.
• Ready for agentic commerce: AI Mode in Google Search has been available in Germany since October 2025, and product data from Merchant Center feeds into its shopping answers. Buying directly in AI Mode or in Gemini via the Universal Commerce Protocol (UCP) is currently only possible for selected merchants in the United States, Canada and Australia, and there is no date for Germany yet. Google’s Business Agent also currently requires an online shop based in the US. OpenAI scaled back direct purchasing in ChatGPT (Instant Checkout) in March 2026. ChatGPT focuses on product discovery and comparison, and purchases are made in the merchant’s own shop.
• What counts in agentic commerce: Google and OpenAI name the same fundamentals: complete required and additional attributes, price and availability identical to the website, well-maintained variants and up-to-date shipping and returns information. With the conversational attributes in Merchant Center, such as “question and answer”, typical customer questions can be stored directly with the product. According to Google, this attribute can be used in all countries.
• Fast updates for price and availability: Google’s Merchant API lets you update the price and availability of individual products without resubmitting the entire feed. According to Google, the changes are usually processed within a few minutes. For product feeds in ChatGPT, OpenAI recommends submitting the full catalogue at least once a day and sending price or availability changes for individual products via the API during the day. Access is currently open to approved partners and geared towards the US. If prices and stock levels change frequently, we can use such interfaces instead of resubmitting the complete feed every time.
• Keeping an eye on changes: the move from the Content API to the Merchant API, pickup_cost being required for pickup products since 30 September 2026, the minimum image size from 31 January 2027: changes like these are a good reason for a feed check. Find out more on our Google Merchant Center page.