Google Comparison Shopping Service Partners, often known as CSS Partners, were introduced after the European Commission fined Google in 2017 for antitrust violations relating to Google Shopping. As part of the ruling, Google was required to change how it operated Shopping ads in Europe to create fairer competition.
This led to the creation of Google Comparison Shopping Services, allowing approved CSS Partners to compete alongside Google Shopping for Product Listing Ad placements.
When a retailer uses a CSS Partner, they can benefit from a 20% advantage in the Google Shopping auction compared with using Google Shopping directly. This can either reduce cost-per-clicks or help improve visibility in the auction.
The main benefit of using a CSS Partner is the potential cost saving.
For example, if you bid £0.50 through Google Shopping, Google takes around 20%, meaning £0.40 is used in the auction. When working with a CSS Partner like Shoptimised, the full £0.50 can be applied to the auction, or you can reduce your bid to £0.40 and aim to maintain the same position at a lower cost.
This means retailers can either reduce bids and maintain similar Shopping visibility, or keep bids the same and potentially improve ad position and impressions.
Unlike Google Shopping, retailers can run multiple Merchant Centers through different CSS Partners. This can be useful for several reasons.
Increased visibility: Working with multiple CSS Partners can help expand your reach and give more products the opportunity to receive clicks. On average, a large portion of shopping feeds receive little to no visibility, so additional CSS activity can help bring more products into play.
Additional support: Each CSS Partner can provide extra support around Merchant Center issues. At Shoptimised, our help desk includes specialists trained to diagnose and resolve feed and Merchant Center problems.
Geographical coverage: Some CSS Partners may be better suited to specific countries or markets. If you are looking to expand into a new country, working with the right CSS Partner can support that growth.
Backup Merchant Center: Merchant Center warnings and disapprovals can happen, sometimes because of issues on the retailer’s side and sometimes because Google has flagged something incorrectly. A CSS Partner can help create a backup Merchant Center, giving retailers more flexibility if account issues occur.
Testing opportunities: At Shoptimised, we specialise in feed optimisation. Having an additional CSS Merchant Center gives advertisers the opportunity to test feed optimisations without affecting their main campaigns.
CSS benefits are currently available in the following countries:
Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
Retailers who also target the USA or other countries outside this list can still run a CSS Merchant Center, but they will not receive the CSS discount in those markets.
Joining a CSS Partner is straightforward. At Shoptimised, we offer free CSS to anyone with a Shoptimised platform subscription, provided the feed is managed through our platform. Other CSS Partners may charge a monthly fee, so the exact setup depends on the provider.
To join a CSS Partner, you will need a functioning Google Merchant Center account, or you must meet the requirements to create one.
A CSS Partner can transfer your Merchant Center from Google Shopping or another CSS Partner. This can take up to 14 days, depending on the current provider. Google switches are usually processed almost instantly, while some CSS Partners may require a delay before releasing the account.
In most cases, no.
Once a CSS switch is initiated, Google Ads campaigns will continue running as normal. You do not need to create new campaigns or pause existing ones.
Your product listings, Merchant Center setup and existing warnings will remain the same. However, if your feed is already disapproved due to an existing issue, switching CSS Partners will not fix that.
One thing to be aware of is account access. If your Merchant Center is part of a Multi-Client Account, it may move under the CSS Partner’s Merchant Center structure. Users with access at the MCA level may need to be re-added after the switch.
Google’s Free Listings can run through Merchant Center, but they can only be active on one Merchant Center at a time.
Free Listings must be configured through a Google Merchant Center. Once an account has switched to a CSS Merchant Center, the option to choose where Free Listings appear may no longer be available.
If you need to change where Free Listings display, you may need to use or create a Google Shopping Merchant Center, or switch the account back to Google.
Yes, you can transfer a Merchant Center back to Google Shopping.
To do this, you need to complete Google’s CSS account switch form. Once submitted, the admin user will receive an email confirming the request. Usually, another email follows within 1 to 4 hours to confirm whether the request can be processed. A switch request will then appear in the General Account Options section of Merchant Center.
Once accepted, the switch usually takes around 24 hours.
It is important to know that the Merchant Center will need to be claimed and verified again after switching back to Google. Until this is completed, products may be disapproved, so it is important to reclaim and verify the website as soon as the switch is complete.
Yes, it is possible to run multiple CSS Partners for the same domain.
A CSS Merchant Center does not need to be claimed and verified in the same way as a Google Shopping Merchant Center, so multiple CSS Merchant Centers can be set up. This allows retailers to take advantage of different CSS Partner offerings and create a more flexible shopping strategy.
However, only one Google Shopping Merchant Center can be claimed and verified per domain. If another Google Shopping Merchant Center is claimed, the original one will lose its claim and verification, and products may be disapproved.
Only one Merchant Center can run Free Listings, and this must be configured through Google Shopping Merchant Center.
No, a merchant is not second-priced against itself.
Google tries not to show multiple versions of the same product from the same merchant. If the same product is uploaded by multiple CSS Partners, Google will usually only show it once in the ad unit.
If different CSS Partners bid on behalf of the same merchant, Google does not use those bids against each other to increase the cost-per-click. For example, if your own CSS bids £0.30 and Shoptimised CSS bids £0.25 on the same product, Google will not use the £0.25 bid to push up your CPC. Instead, Google looks for the next highest bid from a different merchant.
This means using multiple CSS Partners should not increase your CPC simply because more than one partner is bidding on your behalf.
Example: How CSS bidding works
Scenario 1
You bid £0.30 per click.
The next highest merchant bid is £0.20.
You win the auction and pay £0.20, which is only the amount needed to maintain your position.
Scenario 2
Shoptimised CSS also starts advertising on your behalf and bids £0.25.
Your £0.30 bid still wins.
Because Shoptimised is bidding for the same merchant, Google does not use that £0.25 bid to increase your CPC. Instead, it looks at the next highest bid from a different merchant, which is still £0.20.
Your CPC remains £0.20.
Scenario 3
Shoptimised CSS places a higher bid than your main CSS.
Shoptimised wins the auction for that product.
Again, Google does not use your other bid to increase the CPC because both bids are for the same merchant. It looks at the next highest bid from a different merchant, meaning the CPC remains based on external competition.
Each CSS Partner is required to have a Comparison Shopping Service website.
This is accessed by clicking the “by CSS partner” link shown under a product listing ad in Google Shopping.
A CSS website must meet certain requirements, including:
CSS continues to grow, and more retailers are expected to work with CSS Partners as they look to improve Google Shopping performance and reduce costs.
At Shoptimised, we are proud to support leading retailers and agencies as their CSS Partner. We offer CSS for free to anyone signed up to Shoptimised and using our feed optimisation software, helping retailers improve visibility, support Shopping performance and get more value from their product feed.
