Google builds its Shopping Graph from the product data merchants send through Merchant Center, and Google says that graph can power AI features such as buying guidance and product recommendations. Get the identifiers right first: a GTIN, or a brand and an MPN. Then fix the title, the description and, for apparel, color, size, age group and gender, and add product highlights and the optional conversational attributes last.
By Margareta Petrovic, CISA, CISSP, founder of Visibility Mesh. Our engine had scored 957 websites as of October 4, 2026. Our team checked every attribute below against Google's Merchant Center help on October 5, 2026.
On June 29, 2026, the owner of a 30 product store asked on the Shopify Community what matters most for Google Shopping, search and AI Overviews. Their list was titles, descriptions, GTINs, categories, structured data and feed attributes. Our answer is identifiers first. The other attributes describe a product, and the identifier tells Google which product you mean.
What does Google do with my product feed?
Merchant Center is where your product data enters Google. Google's help page on shopping sources says this data feeds the Shopping Graph. Google then uses the Shopping Graph in Search, Ads and YouTube. It also uses it in generative AI features, such as buying guidance and product recommendations.
Anything missing from your feed is something Google cannot say about your product. On Shopify, the Google & YouTube sales channel builds the feed from your product data. Most fixes therefore happen in your Shopify admin, not in Merchant Center.
Why do GTINs and identifiers come first?
A GTIN is the number behind the barcode. Google accepts UPC, EAN, JAN, ISBN and, for multipacks, ITF-14. Google's GTIN page says accurate matching cannot be assured without it. Matching is how Google ties your listing to the same product sold elsewhere, and to that product's reviews.
Google also warns against wrong numbers. Do not guess a GTIN, and do not use the restricted ranges that start with 02, 04 or 2, or the coupon ranges that start with 05, 98 or 99. Google's advice for an unsure GTIN is to leave it out.
A product with no GTIN needs a brand and an MPN instead. The MPN must come from the manufacturer, not from your own numbering. Set identifier_exists to no only for custom or one of a kind goods. Goods made before GTINs existed, such as antiques and books printed before 1970, can also set it to no.
In Shopify, the GTIN goes in the barcode field of each variant. If a product has a GTIN, Shopify will not publish it to Google until you enter it. Brand and MPN for products without a GTIN go in the Google & YouTube channel's product fields. Our article on GTIN, MPN and SKU explains how the 3 identifiers differ.
How should I write titles and descriptions for the feed?
A Merchant Center title can run to 150 characters, and Google says shoppers often see only the first 70 or fewer. Put the product type, the brand and the deciding detail first. Google suggests variant details such as color and size in the title.
A description can run to 5,000 characters. Google asks for the most important details in the first 160 to 500 characters. It also bans promotional text in the description, such as price, sale dates and shipping, and it bans links. The description must agree with the title and with your product page.
The Google & YouTube channel can take titles and descriptions from your product data or from your SEO fields. Pick one source on purpose and check what Google receives. If you wrote careful SEO titles but the channel sends your product titles, Google never sees the SEO titles.
Which attributes do apparel and other categories need?
| Attribute | What Google expects |
|---|---|
| color | Required for apparel in several countries, including the US and the UK. Up to 40 characters, and up to 3 colors joined with a slash. |
| size | Required for clothing and shoes in the same countries. Use the size system shoppers in that country know. |
| age_group and gender | Required for apparel in the same countries. Age group is newborn, infant, toddler, kids or adult. Gender is male, female or unisex. |
| material and pattern | Required when your variants differ by material or pattern. |
| google_product_category | Shopify says to add one to every product. Use the most specific category in Google's list. |
| product_type | Your own category path, such as Women > Coats > Wool coats. |
| condition | Optional for new goods and required for used or refurbished ones. |
Shopify adds 2 rules of its own. Apparel needs age group, gender, color and size in the Google & YouTube channel. Product options and variant names must be in English to sync.
Which attributes does Google tie to AI Mode?
Product highlights are short factual statements about the product. Google allows 2 to 100 of them, each up to 150 characters, and recommends 4 to 6. Promotional text is not allowed. Product details hold technical specifications as a name and a value, up to 100 per product.
Google also has 6 optional conversational attributes: question and answer, document link, related product, item group title, variant option and popularity rank. Google says they help AI systems and conversational agents understand your products. Its help page names AI Mode in Search. Adding them does not change the approval status of your products. Google recommends a supplemental data source for them. That is a second file that adds attributes to products you already send.
For question and answer, Google asks you not to repeat what your description, highlights or details already say. Fill question and answer from your own inbox. Use the question customers send before they buy, such as whether a coat fits over a suit jacket, and answer it plainly.
Why must my product page match my feed?
Merchant Center can update price and availability from the structured data on your product pages. Google calls this automatic item updates. Google's description rules ask you to keep the feed consistent with your landing page.
Product data is the layer most stores get wrong. In our study of 216 Shopify stores, published June 28, 2026, only 27 passed all 5 layers we measure, and the product and brand layer was the weakest of the 5.
In what order should I fix my feed?
Fix a feed in this order: products that cannot appear at all, then products Google cannot match to anything else, then the titles and descriptions.
Your feed checklist
You can work through every step in Merchant Center and your Shopify admin.
- Open Products in Merchant Center, then the Needs attention tab, and fix every product marked Not approved.
- Add the GTIN to the barcode field of each Shopify variant that has one. Leave it empty if you are not sure.
- For products with no GTIN, add the brand and the manufacturer's MPN in the Google & YouTube channel.
- Set a specific Google product category on every product, and fill age group, gender, color and size on apparel.
- Move the deciding detail into the first 70 characters of each title, starting with your 10 best sellers.
- Check that the first 160 characters of each description state what the product is, with no price or shipping text.
- Add 4 to 6 product highlights to your best sellers, then try the question and answer attribute on 5 of them.
When does it make sense to hire help?
Most of this checklist is data entry, and the owner who knows the products does it best. The markup on the product page is harder, since a theme or an app can output structured data that disagrees with the feed. Fixing that means editing templates.
Schema Mesh covers that on Shopify and WordPress for $5,000. It includes everything in Foundation, our $3,000 package, and adds one connected layer of structured data from your own products, for up to about 300 products or 100 pages. You approve every change before it goes live, and your Merchant Center account stays yours.
Questions owners ask
Do I need a GTIN for every product on Google Shopping?
If the manufacturer gave a product a GTIN, you need to supply it. Shopify will not publish such a product to Google until the GTIN is added in the variant's barcode field. A product with no GTIN can still be listed with a brand and an MPN, and custom or one of a kind goods can set identifier_exists to no.
What do I do if my products have no barcode?
If you make the products yourself or they are one of a kind, set identifier_exists to no. If a manufacturer made them, ask the manufacturer for the GTIN or the MPN. Do not invent either number, since Google says an unsure GTIN should be left out.
Where do I add a GTIN in Shopify?
Add it in the barcode field of each product variant in your Shopify admin. The Google & YouTube channel sends that barcode to Merchant Center as the GTIN. Each variant needs its own GTIN, since each size and color is a different product to Google.
What are conversational attributes in Merchant Center?
They are 6 optional attributes: question and answer, document link, related product, item group title, variant option and popularity rank. Google says they help AI systems and conversational agents understand your products, and it names AI Mode in Search. They do not change the approval status of your products.
Do product highlights help in AI Mode?
Google's help pages describe product highlights and the conversational attributes as ways to help AI driven surfaces such as AI Mode understand your product. Google does not promise that any attribute gets you shown. Write 4 to 6 factual highlights, with no promotional text, on your best sellers first.
Can I make up an MPN for my own products?
You should not. Google asks for the manufacturer's MPN, not your own SKU. If you are the maker and the product is custom or one of a kind, set identifier_exists to no instead.
Does Merchant Center data reach ChatGPT?
Merchant Center sends your data to Google, not to OpenAI. OpenAI says product data from Shopify merchants already reaches ChatGPT through Shopify Catalog, with no extra work from the merchant. The same clean identifiers, titles and descriptions serve both, so you fix them once in Shopify.
Make your product pages agree with your feed
Google reads your product pages as well as your feed. The free scan checks the structured data and text on 5 key pages of your store and gives you a 0 to 100 score and a fix list in priority order. No card is needed, and you can compare its findings with your Needs attention tab.
When the markup your theme and apps print is the problem, tell us about your store through the quote form, and someone on our team replies within 1 business day. Schema Mesh rebuilds that markup from your own products on Shopify or WordPress, and you approve every change.
Related reading: If Merchant Center is not connected to your store yet, we show how to connect GA4, Search Console and Merchant Center to Shopify.
Sources
Our team opened every source below on October 5, 2026.
- Sources of shopping info, Google Shopping Help (Merchant Center, Shopping Graph and generative AI features).
- Product data specification, Merchant Center Help.
- GTIN [gtin], Merchant Center Help.
- About Global Trade Item Numbers, Merchant Center Help (GTIN formats).
- Brand [brand], Merchant Center Help.
- MPN [mpn], Merchant Center Help.
- Identifier exists [identifier_exists], Merchant Center Help.
- Title [title], Merchant Center Help.
- Description [description], Merchant Center Help.
- Color [color], Merchant Center Help; also size, age group, gender, material, pattern, Google product category, product type and condition on their own attribute pages.
- Product highlight [product_highlight], Merchant Center Help.
- Product detail [product_detail], Merchant Center Help.
- How to use conversational attributes, Merchant Center Help.
- About automatic item updates, Merchant Center Help.
- Google & YouTube requirements, Shopify Help Center.
- Shopping with ChatGPT search, OpenAI Help Center (Shopify Catalog).
- Prioritization, Shopify Community, thread started June 29, 2026.
- Research and Press, Visibility Mesh, benchmark figures measured October 4, 2026.
- The State of AI Visibility 2026, Visibility Mesh, 216 Shopify stores, published June 28, 2026.