Google Shopping and marketplaces: preparing your store

Why everything starts with product data

Preparing your store for Google Shopping and marketplaces means, first of all, preparing your product data. These channels do not sell your products for you: they publish the data you give them. If that data is incomplete or wrong, products are disapproved or shown less often. The condition for everything else is a clean catalogue, kept in one place, from which every channel is fed.

This work is also the starting point of a store ready to sell, with an imported, cleaned and enriched catalogue. What follows relies on Google’s official Merchant Center documentation, which we cite at each step.

What Google asks for, attribute by attribute

The Merchant Center product data specification lists the attributes required for all products:

• an identifier (id), unique, 50 characters at most;
• a title (title), 150 characters at most;
• a description (description), 5,000 characters at most;
• a link (link) to the product page;
• an image link (image_link) to the main image;
• availability (availability): in stock, out of stock, preorder, backorder;
• a price (price), with its currency.

The condition (condition) is added for used or refurbished products.

These attributes seem obvious. The trap lies rather in the mismatch between the feed and your pages.

The GTIN: the detail that makes the difference

The GTIN is the product’s international barcode (EAN in Europe, UPC in the United States, ISBN for books). Google’s page on the GTIN attribute recommends it for all products to which the manufacturer has assigned one, and specifies that a product’s visibility may be limited if its GTIN is missing or incorrect. It has 8, 12, 13 or 14 digits depending on the type.

Two cautionary rules, from Google itself:

• Only enter a GTIN if you know it. The same page says so: when in doubt, do not provide one, and do not try to guess it or make one up.
• Only set the identifier_exists attribute to “no” if the product really has no brand, no GTIN and no manufacturer part number. According to the product data specification, a product that has identifiers but is declared without them may be disapproved.

For your own creations (handmade products, an own brand with no barcode), the GTIN question arises differently: handle it product by product, not in bulk.

The category: let Google handle it, except in special cases

It is tempting to fill in each product’s Google category by hand. Yet Google’s page on google_product_category states that the attribute is optional: Google automatically assigns a category to every product, and accurate titles, descriptions, prices, brands and GTINs help it do so. The attribute is mainly used to correct a category assigned in error, to organise Google Ads campaigns, and in a few special cases such as alcoholic beverages. A good title and a good description therefore do more than a category filled in by hand.

Shipping and returns: declare them first

According to Merchant Center help, Google’s free listings are turned on by default in most cases. They require you to follow Google’s product policies and, in both France and Belgium, to configure shipping, in Merchant Center or in the product data. For returns, the help page asks you to publish your return policy on your website, so that it can be displayed next to your products, and recommends adding it in Merchant Center too. Finally, it points out that being allowed to appear does not guarantee being shown.

In practice: before thinking about advertising, check that your shipping costs and delivery times, and your return policy, are declared in Merchant Center and consistent with your pages.

Structured data on your pages

In addition to the feed, Google reads the Product and Offer markup on your pages. Its documentation on merchant listing structured data explains that this markup can make a page eligible for several displays in search (the Shopping knowledge panel, Google Images, popular product results, product snippets), and specifies that only pages where the shopper can buy the product are eligible. Price, availability, shipping and returns can appear there.

The feed and the markup must therefore say the same thing as the visible page.

Marketplaces: the same foundation, with extra requirements

Each marketplace has its own format, its own categories and its own required attributes. But all of them rest on the same foundation: an identifier, a title, a description, images, a price, stock, and often a GTIN. The exact rules change from one platform and one category to another: read each one’s seller documentation before committing.

The costliest trap is duplicate data entry: stock and prices end up diverging, and you sell a product you no longer have.

When the ERP drives stock, the choice of platform matters: it is one of the criteria in our comparison Shopify or Medusa for an SME.

The method, in order

1. 01Choose the single source.

   Decide where the product data lives, and stick to it.

2. 02Clean the catalogue.

   You need unique identifiers, clear titles that say what the product is, real descriptions, images of the product and verified GTINs.

3. 03Align pages and feed.

   The page and the feed give the same price, the same availability and the same shipping information.

4. 04Open Merchant Center.

   Declare shipping and returns, send the feed, then fix the disapprovals one by one.

5. 05Add one marketplace at a time.

   Wait until the first channel is stable before opening another.

6. 06Monitor.

   A feed degrades over time (new products filled in badly, stock-outs that are not synchronised). A regular check of disapprovals in Merchant Center is better than one big clean-up a year.

Honest limits

A clean catalogue does not create demand. It lets your products be shown correctly; it guarantees neither how often they are shown nor sales, which depend on price, the offer itself and competition. And marketplaces have their own visibility logic, over which you have little control.

Where to start

Take a handful of your best sellers and check, for each one, that the page, the feed and the markup say the same thing: price, availability, shipping, identifiers. The gaps found in this sample show where the work lies across the whole catalogue. If you are rebuilding your store, this clean-up is part of our store ready to sell in six weeks, with the catalogue reviewed before publication. The other decisions about a store (platform, migration, data) are gathered in our e-commerce section, and what can be automated around the catalogue (emails, posts, reports) in our guide to marketing automation, with and without AI.

Frequently asked questions

Sources

1. Merchant Center product data specification (new tab)support.google.com
2. Google’s page on the GTIN attribute (new tab)support.google.com
3. Google’s page on google_product_category (new tab)support.google.com
4. Merchant Center help (new tab)support.google.com
5. Documentation on merchant listing structured data (new tab)developers.google.com
6. Google’s page on best practices for B2B advertising (new tab)support.google.com