Google Merchant Center

Once Google is connected, Settings → Google → Merchant Center is where your catalog actually syncs to Google.

Choose your Merchant Center account

If your Google account has access to more than one Merchant Center account, select the one Máximo should sync to from the Merchant account field. Máximo lists every account your connection can access, with its name and ID.

Selecting an account:

Saves it as your sync target.
Sets up a primary data source in Merchant Center for your primary market, if one doesn’t already exist.
Starts your catalog syncing on your chosen sync schedule.

How products map to Merchant Center

Each Shopify product variant becomes one item in your Merchant Center feed, identified by a product ID. You choose the ID format from Product ID format:

Format	Example	Use when
Variant + market (recommended)	`shopify_us_8821024_44710288`	You sell in more than one market
Variant ID only	`44710288`
Product + variant ID	`8821024_44710288`
Product ID only	`8821024`	Every variant should share one listing ID
SKU	`MX-TEE-NAVY-M`	Your SKUs are unique per variant

To pin an individual variant’s offer ID regardless of the format above, set a Máximo: Offer ID value on that variant in Shopify admin, it always takes priority.

Changing the format re-creates your listings on Merchant Center under new IDs, which resets Google’s performance history and review status for them. It applies on your next sync.

Variants and size

Merchant Center accepts only one size per listing, it has no field for multiple sizes on one item. If a Shopify product has separate variants for each size, Máximo syncs each one as its own listing and groups them together so Google can show them as size options on the same listing. If a product only has a single variant (for example, sizes listed in the description instead of as an option), Google only ever receives that one size.

To get every size showing correctly:

In Shopify, add a Size option to the product with one variant per size you sell.
Keep other options (like color) on the same product so the variants stay grouped.
Re-sync, either wait for your next scheduled sync, or trigger one manually.

Existing Merchant Center listings on first connect

If your Merchant Center account already has products in it when you connect (from a previous integration, for example) Máximo scans them and tries to match each one to a product in your Shopify catalog, so you don’t end up with duplicate listings. Matching checks, in order:

GTIN/barcode: a barcode on a Shopify variant matching a Merchant Center listing’s GTIN.
SKU: a Shopify variant’s SKU matching the listing’s MPN.
Title: a close match between the listing’s title and a Shopify product’s title.

You can re-run this scan any time from Rescan import next to the catalog status, and review what it matched from Review matches.

Seeing product-level issues

When Google flags a problem with a specific listing, Máximo surfaces it in two places:

On the product itself: open the product in Máximo, expand its Google Merchant Center card under Destinations, and any issue Google reported for that product shows there, a disapproval (which stops the listing from serving) or a warning, with Google’s own description of the problem.
On the Merchant Center tab: if the same issue is affecting most of your catalog at once (like shipping not being set up, or your account pending Google’s initial review) Máximo shows it as a single banner at the top of the tab naming the one thing to fix, instead of listing it separately under every affected product.

Shipping services and rates

Google requires shipping information before it will show free listings and Shopping ads. Máximo takes your Shopify shipping rates as the source of truth and sends them to Merchant Center, so you configure rates in one place rather than maintaining a second copy in Google.

This section needs permission to read your shipping rates. If Máximo does not have it yet, the section shows a button to grant it, Máximo only asks when you use the feature.

The status line tells you where things stand: Not synced, Synced with the time of the last successful push, or Sync error with what went wrong. There is also an option to advertise free shipping on subscription products.

Order tracking signals

Sharing fulfilled order data with Google lets it show accurate delivery estimates in your Shopping ads, which is one of the signals Google uses to rank listings.

Máximo syncs this once a day, and the first run backfills up to six months of order history so Google has enough data to work with immediately. Like shipping, this needs permission to read your orders and asks for it only when you turn the feature on.

Use Excluded order tags to keep specific orders out of the sync, add a tag and press Enter. Any order carrying one of those tags is never sent to Google, which is useful for test orders, wholesale, or staff purchases.

Automated discounts

Máximo can apply a discount at checkout only for shoppers who arrived from a Google Shopping listing showing that price, so your ad price and your checkout price agree without discounting the same product for everyone.

You control:

Whether it is enabled.
A floor percentage, so a discount never takes a product below the margin you are willing to accept.
The discount label the shopper sees at checkout.
Excluded products and collections that should never be discounted this way.

This feature needs permission to view and create discounts. Máximo requests it when you enable the section, not at install.

Next steps

Ads, GA4 & tag: set up conversion tracking.
Event delivery: see what’s sending to Google.
Per-destination overrides: customize a product’s title, description, or images for Google specifically.