For the main-domain we are using reviews.io to collect reviews - unfortunately I can only use it for one domain. Currently we do not have the money to just activate it for all other domains.
My idea was to set up google product ratings (the add-on from the google merchant center) inside shopify on all other domains except the main-domain.
Somehow it is not working. Has anyone done this yet? Any tutorials for this specific case?
so, the reviews. io app that you mentioned is as such popular. i think you should talk to their team or go with some other app through which you collect reviews for all domains. because once those reviews are collected, the app will enable you to send product review feeds to Merchant Center and then on GMC, further mapping of your Google shopping feed and reviews feed will take place.
did you try reaching out to reviews . io team?
also, for these domains do you have the advanced GMC account setup? so that these domains are considered as sub accounts?
Yes, the google customer review app, doesn’t work in Shopify natively. That is because Shopify pixels do not allow popups, while the google customer review system requires a popup.
The solution is to use a 3rd party app. This app redirects the user to a different page, where it then shows the pop-up.
But I would not use google customer reviews, because you can not leave reviews.
Hi Amlani. We are already doing this with reviews.io but only for the main domain. I talked to them and we have to pay extra for every market (in our case subdomain). This would mean a 5x prize increase which makes no sense.
Our GMC is a bit of a mess. It looks like this (I shortened the urls to avoid advertisement):
The issue isn’t really Shopify or the app - it’s how Google matches reviews. Product ratings are tied to product + domain, so reviews from your main domain won’t reliably show on other domains/subdomains.
Even if you reuse the same products, Google treats those domains separately unless everything (feed, domain, review feed) is aligned.
That’s why most setups either:
use one primary domain for all markets, or
send a unified review feed that matches the same product IDs across all domains.
Yes, you can do that. It works best if your products share consistent global identifiers (like GTINs) across all domains.
If you don’t have that, matching across domains becomes unreliable, and many reviews may stay ‘unmatched’ because Google sees different URLs for the same product.
Start by checking if your products actually have matching GTINs across all your feeds. That’s the key factor. Without it, results tend to be inconsistent.
@Alsok, can you provide more evidance regarding you are able to get the Google Customer Reviews to work in Customer Events (pixels)
As of writing it is not possible due to popups being blocked. But if you say it is possible, considering you said it’s not a shopify or app issue, I would love to learn how you managed to get it to work. A step by step guide would be appreciated as that will help everyone. Thank you.
You’re absolutely right about Customer Events - the sandboxed environment prevents triggering the Google Customer Reviews opt-in popup natively.
However, that’s a different program. We’re not talking about Google Customer Reviews here, but about Google Product Ratings via an XML feed. Since the merchant is already collecting reviews via reviews.io, there is no need for the checkout popup or pixel-based integration at all.
The challenge is purely on the Merchant Center side: how Google matches existing review data to products across multiple domains (which relies heavily on consistent identifiers like GTINs, MPNs, and Brand+Title matching).
So the pixel limitation you mentioned is totally valid, just not relevant to this specific setup.
Based on your setup, the issue usually comes from 3 areas:
Missing or inconsistent GTIN/MPN across feeds → breaks product matching
Attribute mismatch between regional stores → prevents aggregation
Review feed validation issues (cross-domain URLs often get rejected)
What you can check right now:
Verify if product IDs are identical across all GMC accounts
Ensure reviews are tied to the same GTIN (not just SKU)
Validate your review feed structure against Google specs
If your reviews.io setup doesn’t expose a direct XML feed, it’s likely using an internal API sync - in that case, you’d need to extract or reconstruct the feed manually.
Unfortunately their app only connects to one GMC ID and not multiple. They said I would need to open several stores to do it with their app. Thank you for the suggestion though.
That is annoying. I recommend look at other review aggregators then.
Or alternatively, restructure how your business works. For example for my clients, I always recommend using 1 domain name to target multiple countries. So instead of a subdomain use a folder system.
