CSS for Google Shopping: what it is and when a Bulgarian store needs it
CSS (Comparison Shopping Service) is a price comparison service through which an online store takes part in Google's Shopping ads in Europe. In 21 countries, including Greece and Romania, Shopping ads and free product listings cannot run without a CSS. Google Shopping itself is also a CSS and retains a fixed margin percentage from the bid, while independent CSS partners work with their own pricing models. For a Bulgarian store, CSS is a question today only when selling in countries on this list. For Bulgaria, Google has announced neither a Shopping launch nor a CSS requirement.
Prepared by Hristiyan Panov, founder of Hpanov-Digital, a performance marketing consultancy with over 5 years of experience and over €2 000 000 in ad spend managed for over 90 companies on Google and Meta. Data last checked: 14.10.2026.
Why do Shopping ads in Europe run through a CSS?
In June 2017, the European Commission fined Google €2.42 billion for giving an advantage to its own price comparison service in search results. Following the decision, Google opened Shopping placements to competing price comparison services. Since then, every Shopping ad in the affected countries has run on behalf of a CSS: either Google Shopping or an independent partner.
For the shopper, the difference is barely visible. Below the ad is the name of the CSS through which it runs, for example "By Google" or the partner's name. The auction, the format and the ad placement are the same.
In which countries is CSS mandatory?
As of 14 October 2026, Google's official page lists 21 countries: Austria, Belgium, Czechia, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
Bulgaria is not on the list because it is not on the list of countries for Shopping at all. More on the status: Google Shopping in Bulgaria: official status.
When does CSS matter for a Bulgarian online store?
When the store sells in a country on the list. The most common cases are Greece and Romania: nearby markets, the euro in Greece and Shopping ads already running in both countries. For products to be shown there, four things are needed:
- Actual shipping to the country, configured in Merchant Center.
- Product pages and a cart in the feed language: Greek for Greece, Romanian for Romania.
- A price in the country's currency or a correctly converted price, as Google requires for the market in question.
- A selected CSS: Google Shopping or an independent partner.
What is the difference between Google Shopping and an independent CSS?
Google Shopping as a CSS retains a fixed margin percentage from the bid. Google does not publish the size of this percentage on its CSS page. Independent partners usually state that the entire ad budget goes into the auction, and they earn from a monthly fee or a percentage of spend. The savings claims in CSS partners' ads are their own and are verified with a test, not taken on promise.
| Criterion | Google Shopping as CSS | Independent CSS partner |
|---|---|---|
| Setup | Default in Merchant Center | Partner selection and linking |
| Payment | Margin retained from the bid | Monthly fee or percentage, depending on the partner |
| Name below the ad | The partner's name | |
| Control over campaigns | Fully in your Google Ads account | In your account, if the partner allows it; checked in the contract |
How should a store choose a CSS partner?
- Account ownership. The Merchant Center and Google Ads accounts must remain in your name. If the contract ends, the data and history stay with you.
- Pricing model. A fixed monthly fee is more predictable with a large budget; a percentage of spend is more cost-effective with a small one.
- Coverage. The partner must support the countries you sell in and, if needed, add new ones without changing the account.
- Status with Google. Google runs a CSS Partner Programme; check whether the selected partner is part of it.
- Term and exit. The minimum term and the termination procedure are checked before signing.
What changes for free product listings?
Free product listings follow the same list of countries as paid ads. In countries where Shopping is not available, including Bulgaria as of 14 October 2026, there are no free listings either. In EEA countries, listings are shown through a CSS on the same principle as paid ads.
FAQ — Frequently asked questions about CSS
What is CSS in Google Shopping?
A price comparison service through which a store takes part in Google's Shopping ads and free listings in EEA countries, Switzerland and the United Kingdom. Google Shopping is one of the CSSs, alongside independent partners.
Is CSS mandatory in Bulgaria?
As of 14 October 2026, Bulgaria is neither on the list of countries for Shopping nor on the list of countries where CSS is mandatory. Google has not announced a requirement for Bulgaria.
Can a store sell in Greece and Romania without a CSS?
No. CSS is mandatory in both countries. If no independent partner is selected, the ads run through Google Shopping as the CSS.
Are ads cheaper through an independent CSS?
It depends on the partner's model and on the budget. Google does not publish the margin percentage that Google Shopping retains, so the comparison is made with a test on the store's own data, not on the partners' advertising claims.
Is control over the campaigns lost with a CSS partner?
It should not be. A correct setup keeps the Merchant Center and Google Ads accounts in your name. This is checked in the contract before signing.
Conclusion
CSS is a condition for Shopping in 21 European countries, and for a Bulgarian store it is a practical question when selling in Greece and Romania. For Bulgaria itself, the decision awaits an official launch by Google. A partner is chosen on account ownership, pricing model and coverage, not on promised savings.
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Related articles: Google Shopping in Bulgaria: status · Merchant Center checklist · Google Shopping for an online shop
