You’ve set up your feed, your products look good and you’re ready to run Shopping ads in the UK or Germany. Then you read that you need a Comparison Shopping Service. What is that? Do you really need one? This guide explains how a Google Merchant Center CSS works and how to choose with care.
A Comparison Shopping Service (CSS) is a website that lets people search for and compare products from many sellers[3]. In 21 European countries, including the United Kingdom, you must use a CSS to place Shopping ads and free product listings on Google[1][3]. The US is not on that list.
Where a CSS is required
Google lists 21 countries where you need a CSS: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Spain, Sweden, Switzerland and the United Kingdom[1][3].
If you sell in any of these, you need at least one CSS to place Shopping ads or free listings[2]. If you sell only in the US, you don’t need one.
Tip
Check the list against your target markets before you plan budgets. If you ship to the UK, Germany and the US, two of those three need a CSS.
How Google Shopping fits in
It is easy to think Google Shopping is separate from CSSs. It isn’t. Google Shopping is itself a CSS[1]. It bids on behalf of its merchants like any other CSS[1]. It is listed as a Premium CSS Partner, with pricing shown as “Percentage of Spend”[5].
So you are not forced to find an outside company. You can choose Google Shopping as your CSS. But it is a choice. Other CSSs may offer different services or pricing.
How a CSS works
Your product data stays in Google Merchant Center. The CSS acts as the business that places your ads in the auction and bids on your behalf[1]. Your ads show a “By CSS” link at the bottom[1].
The CSS pays Google for the clicks. It then decides how to invoice you[1]. In the case of Google Shopping, a fixed percentage margin is deducted from each bid and included in the cost per click (CPC)[1].
How CSSs charge
A CSS typically charges a fixed-percentage markup on the CPC paid in the auction[2]. With a markup, the CSS adds its percentage on top of the CPC you pay in the auction. Rates depend on the provider, so this guide does not quote a figure. Ask each provider for its exact rate in writing.
There are three service models[2]:
- Managed: the CSS runs your Shopping campaigns for you.
- Self-service: you run the campaigns yourself and the CSS provides the access.
- Hybrid: a mix of both.
Choose the model that fits your team. A managed service may suit a small team with no ads expert. Self-service may suit a team that already knows Google Ads. For a wider view of what you pay in total, read https://oxfordimpulse.com/is-google-merchant-center-free-what-you-pay/ and then compare it with your CSS quotes.
Can you use more than one CSS?
Yes, with limits. You can use multiple CSSs at the same time[1]. But one Merchant Center account can be associated with only one CSS at a time[2]. In practice, you can work with several CSSs, but each Merchant Center account links to just one.
The CSS dashboard in Google Merchant Center lets you choose which CSSs promote your products[4]. It also lets you select one CSS for free listings in Europe[4]. Open it before you launch, so you know which CSS gets which products.
Be careful: Don’t change CSS partners in the middle of a busy sales period without a plan. Ask the new partner how the switch works and how long it takes.
How to choose a CSS partner
Start with the Comparison Shopping Partners portal. You can filter partners by country, industry and language[2]. That is useful if you sell in several markets or need support in a language other than English.
Partners are split into two tiers: Partner and Premium Partner. The tier depends on merchant numbers and impression ranking[6]. A higher tier shows scale. It does not tell you whether the service suits your business, so check the other points too.
Compare each option on these points:
- Fee: ask for the exact percentage markup and what it applies to.
- Service model: managed, self-service or hybrid. Pick the one that matches your skills.
- Countries and languages: check that your markets are covered and that you can get support you understand.
- Industry experience: a partner that knows your product type may spot feed problems sooner.
- Reporting: ask what data you will see and how often.
- Invoicing: check how, when and in which currency you are billed.
Ask two or three partners the same questions and compare the answers. If an answer is unclear, ask again. A good partner should be able to explain its terms clearly.
Good to know
Google also sets requirements for CSSs that join its programme[3]. You don’t need to read them all, but they explain what Google expects from a CSS.
What to do first
- List the countries where you want to sell.
- Mark which ones are on the CSS list.
- Open the CSS dashboard in Google Merchant Center and see what is already linked[4].
- Shortlist two or three partners from the portal.
- Ask each for fees and service model in writing.
- Link one CSS, test with a small budget, then review the results after a few weeks.
For more help with your setup, read https://oxfordimpulse.com/google-merchant-center/ next. Oxford Impulse can also help you compare CSS partners.
FAQs
What is a CSS in Google Shopping?
Do I need a CSS to sell on Google in the UK?
Do I need a CSS to sell on Google in the US?
No. The US is not on the list of countries that require a CSS. You can run Shopping ads there without one.
Is Google Shopping a CSS?
How much does a CSS cost?
Can I use more than one CSS?
How do I find a CSS partner?
What are the different CSS service models?
There are three: managed, self-service and hybrid[2]. In a managed model the CSS runs campaigns for you. In self-service you run them yourself. Hybrid mixes both.
What does “By CSS” mean on a Shopping ad?
It is a link at the bottom of a Shopping ad[1]. It shows that a Comparison Shopping Service placed the ad for the merchant.
Where do I choose my CSS in Google Merchant Center?
Use the CSS dashboard. It lets you choose which CSSs promote your products and select one CSS for free listings in Europe[4].
Sources
- Google Merchant Center Help: About advertising with Comparison Shopping Services support.google.com
- Google Merchant Center Help: Working with Comparison Shopping Services support.google.com
- Comparison Shopping Services Help: CSS program requirements support.google.com
- Google Merchant Center Help: About the Comparison Shopping Services dashboard support.google.com
- Comparison Shopping Partners: Google Shopping comparisonshoppingpartners.withgoogle.com
- Comparison Shopping Partners: Partners overview comparisonshoppingpartners.withgoogle.com
