Google Shopping CSS Ads: what options do you have?

  • 8 min read
CSS - which stands for Comparison Shopping Services, has become one of the most talked-about buzzwords of this year in the online advertising industry.

Everything started with the massive EU antitrust regulation's fine that hit Google in 2017 over its shopping service. Following the regulation, Google had to make its Google Shopping service profitable on its own and open the shopping section on the general search results page to other competitors.

By now, you're likely familiar with the new look of shopping results on the general search results page:

SERP-results-css-adsYou might have noticed new blue labels placed at the bottom of shopping ads, "by Google", "by DFW Shopping", "by another CSS".
Clicking on that blue label you can access the CSS' website to view more results and compare more products by the same CSS. A click on the product title or image, will result in landing directly on the merchant's product page.

Today other companies, known as Comparison Shopping Services (CSSs), can advertise on shopping ads on behalf of merchants, the same way Google Shopping does. Both Google Shopping and CSSs make bids to compete in the ad auction. In fact, Google Shopping is also a CSS itself.

As a merchant you necessarily need a CSS to place your ads in the shopping bar on top of the Google search results page. The CSS of your choice can either be Google Shopping or another one or both - you can even place your ads through several CSSs.

The Problem

While before the regulation all merchants had to place shopping ads directly through Google Shopping and so directly paying Google, now they can choose a third-party CSS to place ads on their behalf. In practice, this means the existence of a new intermediary between merchants and Google.

Obviously, the first thing that would come across your mind reading these lines is that third-party CSSs need a cut too and so the overall cost of Google Shopping would actually increase for advertisers.

So, why would a merchant bother to go to a third-party CSS and pay them an additional fee?

Google addressed this problem with a simple solution: monetary incentives.

The Google solution: Incentives

Google decided to grant discounts to merchants who would advertise through a third-party CSS. In the early stages of the CSS program the benefits included:

  • SpendMatch Incentive: in which Google was crediting a percentage of monthly ad spend back to merchant's account to be used for future spend
  • Up to 20% discount for clicks

As of January 2019, Google withdrew the SpendMatch, leaving the up to 20% discount for clicks on the table for any merchant willing to advertise via another CSS (non-Google) on Google Shopping. Although there is no official statement from Google on how long the discount for clicks will be around, many industry experts estimate that Merchants will have access to this benefit for at least a few years time. 

It's worth mentioning that the Google CSS program is only available for merchants advertising in countries that are part of the European Economic Area (EEA) and in Switzerland.

Fix your feed errors today! Get a FREE mapping roadmap to fix all your Google Merchant Center errors 

What do CSSs do for merchants?

The short answer to this question is: CSSs allow merchants to access the Google incentive program and therefore save money on their online advertising.

In fact, Google Shopping and other CSSs have access to the very same set of features, bidding strategies and placements available in Google Ads. From a campaign management point of view, there is no difference at all between advertising through Google Shopping and a third-party CSS.

However, given that CSSs are usually part of the services provided by medium/large ad tech providers or marketing agencies, they often offer an expert in-house team and sometimes even advanced in-house technologies that can boost PLAs campaign performance.

So, advertisers who join CSSs not only get a monetary discount on their ad campaigns, but might also achieve improved performance, due to the specialized expertise of CSSs.

How much does it cost?

As mentioned above, CSSs take a cut of your ad spend. So you have to measure if the cut they ask for is worth the potential saving you're getting.

CSSs charge their customers based on several different pricing models. Some charge per click, some per sales, some just a fixed fee. Some CSSs provide additional bidding and feed management technology, others just the access to the Google incentives. Obviously, the former would charge a higher fee than the latter.

There is really no one-size-fits-all approach here as every CSS is different and it is up to advertisers to choose the one which best suits their needs. As mentioned before, advertisers can work with multiple CSSs at the same time. So it might be worth trying a few of them first and then decide which one to go with. Advertisers can also decide to advertise only a portion of their catalogue through a specific CSS. So, again, it is a matter of testing and finding the right balance for your business.

Our own CSS at DataFeedWatch for example, only charges a small percentage of your ad spend without any additional fees. 

Getting started

In order to start advertising through a CSS, you first need to choose the one you want to work with and contact them to find out what their pricing model is, how much they cost and what they offer.

Based on their cost and services provided, the approach to start showing your products on Google might differ:

Managed service

Some CSSs offer you to fully manage your shopping campaigns on your behalf. They would create a new Google Ads account and a new Merchant Center account where to upload your product feed.
You may or may not have access to these accounts.

The only thing you need to provide them with is your product feed. Usually, these CSSs also offer a feed management and optimisation service through an owned or third-party tool. Again, you might or might not have access to this tool.

Google will invoice the CSS for clicks on the ads they place on your behalf and then, in turn, the CSS will charge you based on the agreement you have in place. The CSS then provides you with performance reports.


In this scenario, you or your CSS create a new Merchant Center account which you definitely have access to. You will upload and manage your product feed as well as manage your shopping campaigns from your own Google Ads account.

As long as the Merchant Center associated with your Google Ads account is linked to a CSS, you are eligible to the incentive program.

This is the approach we follow at DataFeedWatch. You can keep your Google Ads account, your Shopping campaigns and your Merchant Center exactly as they are. The only thing that needs to be done is linking your current Merchant Center account with the DataFeedWatch Multi-Client Merchant Center account. This way, Google will associate your shopping campaigns with a CSS and allow you to save.

In this scenario, you might create multiple Merchant Center accounts, one per every CSS you work with. Then you can run multiple shopping campaigns, each one associated with a different Merchant Center. This way you can compare performance from different CSSs as well as potentially increase your exposure on the Google shopping results.

In this setting, Google invoices you for your ad clicks and then the CSS charges you separately.

Hybrid models

As said, there is no one-size-fits-all approach when it comes to working with CSSs. Many of them offer a hybrid approach where they might provide you with a feed optimization service, but then you manage shopping campaigns yourself, or the other way around.

In this setting, you might link your existing Merchant Center account to the CSS multi-client account, or create a new one. You might create a new Google Ads account or keep using your existing one, and so on.

Charging models and invoicing systems might also differ.

How the auction works

As mentioned above, you can advertise on Google through multiple CSSs at the same time, including Google Shopping. This means that different CSSs might show your products several times next to one another.

Google stated they do their best not to show the same product from the same merchant multiple times. However, it is something you need to take into account. Actually, this doesn't need to be a downside - in fact, it could be a way to increase your reach and exposure.

The only problem you might think of is that you could end up paying more just by competing against yourself. Well, fortunately, Google has already provided a solution to this.

This Google Help Center article gives us the answer:

Will I end up paying more for Shopping ads if more than one CSS advertises on my behalf?

"A merchant will never be second-priced against itself in the auction for any offer, and that rule holds irrespective of the number, or identity, of the CSSs used by the merchant."

You will always pay just as much as you need to beat your closest competing merchant.

If you are competing against another CSS advertising on your behalf, its bid won't be taken into account for the calculation of your cost per click. Rather, only the bid from your closest competitor will be taken into account.

Google gives insightful tables to better understand this important concept:

Examples: CSS A bids 30 pence per click to place your offer. For simplicity, we'll assume that all ads have the same quality and relevance.

First scenario: The next highest CSS bid is 20 pence on behalf of a different merchant. Your offer will win the auction at a cost of 20 pence – only as much as necessary to maintain the position.
css-bidding-tableSecond scenario: Now assume that another CSS starts advertising on your behalf and bids 25 pence. You still win the auction with the 30 pence bid that CSS A made on your behalf, but the next closest competitor now bids 25 pence. Since this competitor is a CSS who's also bidding on your behalf, we do not use that second bid to determine the price that CSS A pays. Instead, we find the next highest bid that's been placed for a different merchant, which is still 20 pence. The CPC paid for the winning bid does not change and remains at 20 pence.
css-how-ad-auction-worksThird scenario: Now assume, instead, that the bid placed on your behalf by CSS B is higher than the bid placed by CSS A on your behalf. In this case, CSS B will win the auction. The next highest bid is the 30 pence bid that CSS A placed, also on your behalf. Since both bids are for the same merchant, we do not use CSS A's bid to determine the price of the click that CSS B pays. Instead, we use the next highest bid for a different merchant, which is still 20 pence. The CPC paid by CSS B for your product will be 20 pence.

Should I bother?

Now the big question is:

I have always advertised on Google Shopping self-managing my campaigns and I have always been pretty satisfied with the performance. Why should I bother working with a different CSS?

The answer is pretty simple. You can save up to 20% on clicks - the saving can either go back to your pocket, or perhaps you could use it to drive more traffic to your ads while keeping the same advertising costs.

If you go for a self-managed model, like the one we offer at DataFeedWatch, you will keep managing your feed and campaigns the same way you always did. The only difference is that you will be eligible to receive the up to 20% discount for your clicks.

Fix your feed errors today! Get a FREE mapping roadmap to fix all your Google Merchant Center errors 


The following FAQs are a recap of the this Google Help Center article:

  • Do I need to use a CSS to place Shopping ads on the Google general search results page?

    Yes, you do. But remember, Google Shopping is a CSS! So, chances are you are already using one :)

  • Will my products be shown several times next to one another?

    Although Google does its best to avoid that, yes it might be the case. Anyway, you will never pay more than what you need to beat your closest competing merchant.

  • Will I end up paying more for Shopping ads if more than one CSS advertises on my behalf?

    As said above, no you won't!

  • How do I know how much CSSs bid in the auction on my behalf?

    In the managed service model, you can't know that. It is up to the CSS to bid what it reckons it needs to get the best ROI. However, you should ask for detailed reports so you can see what's the average cost per click.

    In the self-service model, you manage campaigns by yourself, so in practice, you are placing bids, not your CSS.

  • Where will my product ads be shown?

    Your products will be shown in the shopping bar at the top of the Google general search result page. Also, they will be shown on the CSS own website. For example, is the Google Shopping own website. You can access this section only through the Google Shopping CSS.

  • Is it better to advertise through a specific CSS?

    Every CSS provides different services and pricing models. In order to find out what is the best CSS that suits your needs, you have to spend time talking to them and possibly trying them out before making a final decision.

    No CSS is necessarily better than others.

  • Can I advertise with multiple CSSs at the same time and switch whenever I want?

    Yes, you can. Based on the agreement you have with your CSS and the model you choose, you can change the CSS you work with every time you want.

  • I get an error in Google Merchant Center "CSS not selected for this destination". How can I resolve it?Learn how to fix the 'CSS not selected for this destination' error in one of our previous articles. 


About DataFeedWatch

DataFeedWatch by is the top-rated global product feed management platform that enables eCommerce brands, retailers, and digital agencies to drive multichannel growth. Merchants on both custom solutions and popular shopping carts, like Shopify, WooCommerce, and Magento (among others), can choose from 2000+ integrated shopping channels, affiliate networks, and marketplaces in 60 countries (such as Google, Facebook, Criteo, Amazon, and more). Major global brands like adidas, Decathlon, and KENZO have used DataFeedWatch to improve product performance across channels and expand to new markets. Sign up for a free trial today and receive guided onboarding to get started.

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