Google Merchant Center: a guide to the product feed and the most common errors

Monday morning, three weeks before Black Friday. The owner of a homeware e-commerce store opens Google Ads and sees Performance Max stuck at half its budget. In Merchant Center, 412 out of 1,300 products are “disapproved”. The most frequent reason is “Mismatched price”: on Friday the website started its sales, the feed updates once a day and Google found different prices on the listing and the page. Nobody touched the campaigns, and yet the campaigns stopped spending.

The short answer: Google Merchant Center is the account where you upload the catalogue that powers Shopping ads, Performance Max and free listings. It works if three things are in order. First, a verified and claimed website with clear contact details, shipping and returns. Second, a data source that updates itself often enough, from a file, Google Sheets, the API or your e-commerce platform’s app. Third, complete attributes consistent with the product page, starting with price, availability, images and GTIN. Most disapprovals come from a difference between what the feed says and what the website shows.

This article is about the catalogue and the account, not the campaigns. If you want to understand how the auction works and when it’s worth investing in Shopping, see Milica’s article on how Google Shopping works; for the format that uses the feed most today, there’s our guide to Performance Max campaigns.

What is Google Merchant Center in 2026?

It’s Google’s free tool where a shop uploads its product data. From there, the data ends up in Shopping ads, in Performance Max campaigns with a catalogue and in free listings.

A note on the name. The old “classic” Merchant Center was replaced by Merchant Center Next for all accounts by September 2024. In July 2026 Google dropped the word “Next”: the tool is once again called simply Google Merchant Center, with no action required from merchants, as stated in the Merchant Center announcements log. Guides that talk about “feeds” and “feed rules” describe the old interface: today we talk about data sources and attribute rules.

Two other changes in 2026:

• Content API for Shopping. The old API for sending products programmatically reached its sunset date on 18 August 2026, with a gradual shutdown. Anyone using it, even through a plugin, needs to move to the Merchant API; files and Google Sheets aren’t affected.
• Unified policies. From September 2026 the policies for Shopping ads and free listings are a single set, with no changes of substance.

How do you open an account and verify your website?

You create the account with a business Google address, enter the business information and then verify and claim the shop’s website. These are two different steps.

Verifying means proving to Google that the website is yours. Claiming means reserving that address for your Merchant Center account: a URL can be claimed by only one account. The verification methods listed by Google are four: HTML tag, uploading an HTML file, Google Tag Manager or Google Analytics. On platforms such as Shopify the Google Analytics method may not work, and Google recommends the HTML tag. The tag must stay on the website afterwards too: if it disappears in a redesign, you lose verification.

Before uploading products it’s worth checking the website. In the new accounts we see, suspensions often come from the misrepresentation policy and depend on what’s missing from the website, not on the catalogue:

What to check	Why
Company name, address, phone, email visible	They must be easy to find and consistent with the data in Merchant Center
Returns page with timescales, conditions and costs	An unclear or unenforced returns policy counts as misrepresentation
Shipping costs and times	They must match those declared in Merchant Center
Prices and availability legible on the product page	These are the values Google compares with the feed

Which data sources can you use, and which should you choose?

A data source is the channel through which Merchant Center receives products. Every account has a primary source, the only one that can add or remove products, and can have supplemental sources that correct or enrich the primary source’s data. Google recommends putting all products in a single primary source.

Source	How it works	Frequency	When we use it
File (CSV, TXT, XML)	Uploaded by hand, via SFTP or Google Cloud Storage, or fetched by Google from a URL	Scheduled fetch, by default every 24 hours; manual upload doesn’t update itself	Management systems or platforms that export a feed
Google Sheets	A sheet template with one row per product	Sync every 24 hours by default, adjustable	Small catalogues, tests, supplemental sources
Merchant API	Your system sends changes product by product	Near real time	Large catalogues, frequently changing prices and stock
E-commerce platform app	Direct connection from Shopify, WooCommerce and others	Automatic sync; the first import can take up to three days	Most e-commerce stores on standard platforms
Products found on your website	Google reads the structured data on product pages	Checked at least every 24 hours	A starting point or safety net, not as the only source

Shopify and WooCommerce

On Shopify the connection goes through the Google & YouTube app, which syncs products with Merchant Center. On WooCommerce you use the official Google for WooCommerce extension. In both cases the same rule applies: data is corrected in the platform, not in Merchant Center, because at every sync the platform overwrites whatever you’ve changed by hand.

The apps do the basic job well; they show their limits when you need titles that differ from the website or labels for your campaigns.

Products found on your website

If the website has correct Product structured data, is verified and its robots.txt doesn’t block Googlebot, Google can create listings on its own. It’s useful to get started, but it doesn’t replace a primary source: you have less control over titles and you can’t add attributes that aren’t on the page. The markup is still needed, for SEO too, as we explain in our guide to e-commerce SEO.

Which attributes are required and which are worth filling in?

The product data specification divides attributes into required for everyone, required in certain cases and recommended. In practice, for an Italian e-commerce store:

Attribute	Status	Practical notes
id	Required	Unique and stable over time. If it changes, the product starts from scratch in campaigns
title	Required	Maximum 150 characters
description	Required	Maximum 5,000 characters, product information only
link	Required	The product page, on the same verified domain
image_link	Required	Main image, without promotional text
availability	Required	in_stock, out_of_stock, preorder, backorder
price	Required	The full price, including VAT, the same as the page
brand	Required for new products	Excluding films, books and music
gtin	Required if the product has one	The manufacturer’s barcode
mpn	Required if there’s no GTIN	The manufacturer’s part number
condition	Required for used and refurbished	Always recommended
item_group_id	Required for variants in free listings	Links sizes and colours of the same model
color, size, gender, age_group	Required for clothing in some countries and in free listings	Always fill them in if you sell fashion
shipping	Required in Italy, in the feed or in the account settings	Better managed at account level
product_type	Recommended	Your internal category, useful for splitting campaigns
sale_price and sale_price_effective_date	Recommended	Essential during sale periods
custom_label_0 … custom_label_4	Optional	Your own labels for margin, season, best sellers

Required attributes get the product approved; recommended attributes and labels decide how well the campaigns work.

How do you write titles and images that work?

Titles

The title is the field with the most influence on which searches trigger the product. Google says users notice at most the first 70 characters, so the important information should go at the start, and it asks you to use the space up to 150 characters for details that set the product apart.

Structures we often use, to be adapted:

Category	Structure	Made-up example
Fashion	Brand + type + gender + material + colour + size	Rossi Women’s white leather sneaker 38
Electronics	Brand + line + model + key feature + capacity	Brand X Wireless headphones HX-200 noise cancelling 30 hours
Home	Type + material + size + colour + brand	Non-stick aluminium frying pan 28 cm black Casa Bella

What not to put in the title: prices, discounts, “free shipping”, capitals for emphasis, the shop’s name. They have dedicated attributes, and in the title they risk getting the product disapproved.

If you generate titles or descriptions with AI, there’s a new rule: Google asks you to submit them with the structured_title attribute (and structured_description), stating that they were generated by an algorithm. It’s not a ban; it’s a mandatory declaration.

Images

The main image must show the product, not a graphic. No promotional text, overlaid logos, watermarks or borders. Google can remove some overlays itself with automatic image improvements, but it’s best not to count on it.

On sizes, there’s a change to put in the calendar. Today the minimums are 100 × 100 pixels, 250 × 250 for clothing. From 31 January 2027 all images will have to be at least 500 × 500 pixels, and Google is already showing warnings for images below this threshold. If your catalogue uses small thumbnails, the work needs planning now.

GTIN: what is it and what if you don’t have one?

The GTIN is the barcode assigned by the manufacturer: 13-digit EAN in Europe, 12-digit UPC in the United States, plus the 8- and 14-digit variants. Google uses it to recognise the product and show it in the right searches.

• Branded products bought from a supplier. The GTIN almost always exists and is on the packaging or in the supplier’s price list. It should be entered. Without it, the product may have limited performance.
• Products you make yourself, handmade or made to order. If you’ve never applied for GS1 codes, the GTIN doesn’t exist. Enter brand and mpn (your part number); if that’s missing too, set identifier_exists to no.
• Own brand with GS1 codes. If you have them, use them: this is where the GTIN helps most.

The non-negotiable rule: never invent a GTIN, never copy one from a similar product, never use one for several products. Google checks that the code is valid and matches the brand.

How do you set up shipping and returns?

In Italy, shipping information is required both for ads and for free listings. The simplest way is to set it at account level, in the Shipping and returns section, and use the shipping attribute in the feed only for exceptions (bulky products, items with dedicated shipping).

For each shipping rule you specify:

• Cost: fixed, free above a threshold, or variable by weight, price or number of items. It must be the same as the customer sees at checkout.
• Cut-off time: the time by which an order is prepared the same day.
• Handling time: the minimum and maximum days to prepare the parcel.
• Transit time: the courier’s working days.

Google calculates the estimated delivery date from the maximum values, so it pays to be realistic.

Returns are set up in the same section: countries, return window in days, who pays for return shipping, any costs, a link to the returns page on the website. What you write must match the website’s returns page.

What are free listings and why switch them on?

Free listings show your products at no cost in the Shopping tab, in Search results, in Google Images and Lens, on YouTube and, according to Google’s guide, in Gemini and Maps too. In new accounts they’re on by default; in existing accounts you check them under Marketing methods.

They don’t replace advertising and Google doesn’t guarantee that products will appear. But they use the same feed, cost nothing and bring traffic you wouldn’t otherwise get. We always keep them on.

What are the most common errors and how do you fix them?

You’ll find errors under Products, in the Needs attention view, with the list of issues, the number of products affected and examples. After a fix, the status can take 24 to 72 hours to update.

Error	Typical cause	How to fix it
Mismatched price	A sale started on the website before the feed updated; price loaded via JavaScript; wrong time zone in sale dates	More frequent updates or the API; sale_price_effective_date with time zone; price in the HTML and in structured data
Mismatched availability	Stock changing more often than the feed	Same approach as for price; for at-risk products, more frequent updates
Image with promotional overlay	“-30%” banner, logo, watermark	A clean photo as image_link; graphics stay on the website
Image too small	Theme thumbnails used instead of the original	Point to the high-resolution file, at least 500 × 500
Incorrect or invalid GTIN	Invented, copied or wrong supplier code	The manufacturer’s code, or brand + mpn
Missing shipping costs	No rule for Italy, or a rule for a different country	Shipping rule at account level
Misrepresentation (account)	Unclear contact details, returns or shipping	Fix the website and then request a review

Automatic item updates: helpful, but not enough

Merchant Center can automatically correct small differences in price, sale price, availability and condition by reading the product page. Automatic item updates are on by default. However, Google describes them as occasional corrections: if prices change more than once a day, or if there are too many differences, they may stop and products get disapproved. If the page shows several struck-through prices, it’s better to switch off the automation for price.

How do you optimise the feed with supplemental sources and rules?

To change data without touching the website or the platform you need two tools: supplemental sources and attribute rules. Both require you to turn on the Advanced data source management add-on in the account settings.

A supplemental source is usually a Google Sheet with the id column and one or more columns to update. It can’t add products: it only changes those that already exist in the primary source, if the ID matches exactly. It’s the most convenient way to add missing GTINs, hand-rewritten titles for your most important products or custom labels.

Attribute rules transform data automatically. The available operations are “Set to”, “Extract”, “Prepend”, “Append”, “Find and replace”, “Calculate”, “Split and choose”, “Optimise URL” and “Clear”. Some practical uses:

• Prepending the brand to the title when the platform exports only the product name.
• Adding colour and size at the end of variant titles.
• Creating custom labels by price band or category.

Custom labels connect the feed and the campaigns

The five custom_label attributes let you split products according to what matters to you and Google doesn’t know: margin, seasonality, best sellers, clearance products, new arrivals.

An example made up for the sake of illustration: a shop with 1,200 products sets custom_label_0 = high, medium or low margin, and custom_label_1 = “black-friday” on the 150 items on promotion. In Performance Max it creates separate asset groups for high-margin products and for promoted products, with different return targets. This is how we work in the Performance Max campaigns we manage: the catalogue split by product line and margin before talking about budget.

How do you get Merchant Center ready for Black Friday?

In 2026 Black Friday falls on Friday 27 November and Cyber Monday on Monday 30. Working on the feed in sale week is the worst possible time: the work needs doing in the four weeks before.

Four weeks before. Clear the open errors in “Needs attention”, starting with the products you want to push. Check GTINs, images and titles of your best sellers. Make sure shipping and returns match the website, including any special conditions for the period.

Three weeks before. Prepare custom labels for promoted products. If the feed updates once a day, consider more frequent updates for the sale period, or moving to the Merchant API if the catalogue is large.

Two weeks before. Set up discounts with sale_price and sale_price_effective_date, with the same date, time and time zone as the website. The full price stays in price. For Google to show a struck-through price, the full price must have been applied for a certain period: for Shopping ads, 5 days in the last 30 or 15 in the last 200. In Italy there’s also the Consumer Code (Codice del consumo) rule on price reduction announcements, which requires you to show the lowest price applied in the previous 30 days: the struck-through price on the website must comply with it, and the feed must be consistent with the website.

One week before. If you want to use Merchant Center promotions (discount codes or offers shown below the product), upload them now. Italy is one of the countries where they’re available; Google recommends submitting them at least 24 hours before they start and review usually takes 12 to 24 hours.

During the sales. Check “Needs attention” every day and don’t change campaign structure and targets at the height of the peak.

Afterwards. Remove the promotional labels and check that prices return to full price in the feed and on the website at the same time.

Mistakes to avoid

Editing products by hand in Merchant Center. With an app or a scheduled file, the next sync wipes out your changes. Data is corrected at the source, or with a supplemental source.

Updating the feed less often than the website. If prices change several times a day and the feed updates once, price disapprovals are only a matter of time.

Inventing GTINs. An invented or copied code does more harm than a missing one.

Using promotional graphics as the main image. The “-30%” belongs in sale_price and in promotions, not on top of the photo.

Ignoring technical deadlines. The end of the Content API and 500 × 500 images from 31 January 2027 can’t be sorted out in a day.

Want a check of your Merchant Center before the peaks?

We review account and catalogue: website verification, data source, attributes, open errors, shipping and returns, custom labels. At the end you get a list of fixes in order of priority and the feed changes your campaigns need. It’s the foundation of our work on Google Ads and Performance Max campaigns for e-commerce.

You can book a call with Federico or write to us using the contact form.

Frequently asked questions

Is Google Merchant Center free?

Yes. The account, uploading products and free listings cost nothing. You only pay for advertising, that is, the Shopping or Performance Max campaigns in Google Ads that use the catalogue.

What’s the difference between Merchant Center and Merchant Center Next?

None, today. Merchant Center Next replaced the classic version for all accounts in 2024, and in July 2026 Google dropped “Next” from the name. Guides that talk about “feeds” and “feed rules” describe the classic interface; today they’re called data sources and attribute rules.

How long does it take for products to be approved?

It depends on the source and the state of the account. Products imported from an e-commerce platform can take up to three days to appear; after a fix, the status can take 24 to 72 hours to update. A new account also goes through a website review, which can lengthen the timescale.

Can I sell on Google Shopping without a GTIN?

Yes, if the product doesn’t have one: handmade goods, made-to-order products, own brands without GS1 codes. In that case you enter the brand and part number, or declare that identifiers don’t exist. If, on the other hand, the product has a GTIN and you don’t enter it, you risk limited performance.

What should you do if your account is suspended?

Read the reason in Merchant Center, fix the website and the data, then request a review. The most frequent causes are incomplete contact details, unclear returns or shipping policies and prices that differ between feed and website. Requesting a review without having changed anything usually leads to another rejection.