The ultimate Google CSS Guide

What is Google CSS?

CSS stands for Comparison Shopping Services – in German price comparison services – and affects the search results on the Google homepage.

Price comparison portals (CSS) can submit bids in order to place shopping ads for retailers they represent on Google search results pages. Google Shopping bids on behalf of the merchants it represents in the same way as any other price comparison website.

This means that you as a retailer can use the Shopping ads on the Google search results page in different ways: You can enter your product data for any price comparison portal, including Google Shopping. But you can also use several price comparison portals at the same time.

Originally, Google used the search results page exclusively for its own price comparison, Google Shopping. Other price comparisons appeared much later in the search results. In this, the European Commission recognized unfair competition because Google exploited its monopoly-like market position to give preference to its own offer.

In order to create equal opportunities, Google opened the advertising platform under the name Google Shopping Europe (GSE) as a price comparison and opened it to external price comparison sites – from so-called Google CSS partners. As a result of this realignment, all shopping ads that appear in Google’s main search results are part of a Comparison Shopping Service (CSS).

Google Shopping itself also functions as CSS („From Google“), takes part in the bidding auction like the other price comparison platforms and competes with other CSSs that submit bids on behalf of retailers.

In order to use your own price comparison in conformity with the EU, however, Google’s own price comparison retains around 20% of the bid of a retailer who uses Google’s own price comparison as a margin. Only in this way can Google Shopping Europe pass as an independent price comparison, which accordingly also has to work in a profit-oriented manner.

However, this reduces the bids of all advertisers who use Google Shopping Europe by around 20%. If you use a CSS partner for your advertisements, the margin for Google Shopping Europe is completely eliminated.

For Google users, the difference is hardly noticeable, the only visible change is the added line „From ….“ at the bottom of the display.

What will change with the use of CSS Shopping?

For you as an advertiser, the composition of your Google Shopping bids, with which you enter the auction for the ad rank, will change in particular:

Let’s say you start with a CPC bid of $ 1. If you are still using Google Shopping Europe, € 0.20 will be deducted from this. The result: For ad rank, you bid with a reduced bid of € 0.80.

If you do not advertise your products via GSE, but via another Google CSS partner, this margin is no longer applicable. The bids are entered in the auction in full, i.e. € 1.

Your advantage: You win significantly more auctions with the same CPC bid and can significantly increase your traffic and sales.

Is it worth switching to a Google CSS partner?

Everyone who runs Google Shopping Ads should switch to Google Shopping CSS with the help of a CSS partner. The effort is minimal, but the benefits are enormous.

In most industries, so many online retailers now use CSS that you are no longer competitive as a shop if you don’t use a CSS partner and go into the auctions with correspondingly lower bids.

Advertisers pay up to 20 percent more per click if they place a Shopping ad via GSE instead of via a CSS partner. In practice, of course, CSS operators also pay for their services. Depending on the provider’s billing model, there is usually an agreed, fixed fee per month. Percentage models are also possible, in which an agreed share of the media spend flows to the CSS operator.

The costs for the CSS, but also the quality of the CSS providers, differ greatly in some cases, especially in terms of support. Compared to the margin charged by GSE, however, the costs for external CSS use are lower in most cases. For advertisers with a manageable budget, however, it is important to check carefully whether working with a CSS partner is worthwhile, or whether fixed fees may offset the savings in the GSE margin.

Strategies & best practices for the optimal use of CSS

If you have decided to switch to a Google CSS partner, the question arises about the optimal account and campaign setup: Does it make sense to move all accounts to a Google CSS partner? Or are there even advantages in the display by dividing the accounts between GSE + CSS? What exactly should the account & campaign setup look like after the move?

Variant 1: The double strategy

With a double strategy, you use Google CSS and Google Shopping Europe in parallel.

With the double strategy, you have the option of providing the traffic with different bids depending on its placement (Google main search and Google Shopping tab & partner networks). This would be particularly useful because the traffic on the Google Shopping tab and the partner networks often perform significantly worse than on the Google main page:

  • High bids on the main page using a CSS account
  • Low bids on Google Shopping Tab & partner networks using a GSE account

So you use different accounts to cover different placements. This strategy is particularly relevant for particularly large advertisers who do not shy away from the increasing effort.

Variant 2: Complete move to CSS

In practice, the double strategy seldom leads to quantifiable added value when the maintenance effort is considerably greater. We therefore recommend the complete move with all accounts and Google Shopping campaigns to CSS.

Due to the low effort, the complete move represents the optimal cost-benefit ratio: Very little effort with full utilization of all CSS advantages.

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The integration: full switch vs. association

In order to display Google Shopping ads via a CSS partner, there are two options for converting an existing Google Shopping Europe account to CSS: Full Switch or Association.

With a full switch, the advertiser’s Merchant Center Account (MCA) is fully integrated into the CSS partner’s Multi Client Merchant Center (MCC). There are some technical aspects to consider when making this move. If not the entire MCA but only a sub-account is moved, it is possible, for example, that the access rights are lost during the move.

The main advantage of the full switch is that the CSS partner has access to the product data. In this way he can identify the causes of problems himself and correct them if necessary. However, the advertiser’s dependency on the CSS partner is higher than with the simple association according to the association model and requires trust between both parties.

If an advertiser chooses the association model, their MCA is linked to the CSS partner relatively easily. The setting of the advertiser can remain unchanged in this case, the relocation effort is very low. An email from the CSS partner to Google is enough to request the changeover. If only one sub-account is converted from an MCA, the same dangers of loss of access rights apply as with a full switch.

The advantages of the full switch method just mentioned (full access to and insight into the product data by the CSS partner) do not have an immediate effect here. However, the CSS partner can be given access to the customer account or data feed via corresponding user invitations.

Full switch and association hardly differ in handling and cooperation. It is more a question of trust, control and flexibility whether an advertiser moves his entire account to the MCC of the CSS partner or is connected via the association.

The CSS checklist

Compare the prices of the individual CSS

Use CSS partners who charge a monthly fee for their service and do not participate on a performance-related basis. Otherwise this could be expensive for you.

The monthly costs can vary considerably, especially if you are active in many countries. So also pay attention to the additional costs for other countries.

In which countries would you like to place ads?

You need a CSS for each country in which you want to place Google Shopping Ads. So check whether your potential CSS partner also compares prices in the countries where you want to sell.

In principle, the need for support after changing the CSS is low

Make sure that your partner has sufficient technical resources and pursues the topic of CSS with strategic relevance in order to minimize your risk as a merchant that the CSS certification will not be jeopardized by future adjustments to the rules of the game on the part of Google.

Look out for short contract terms of less than 6 months, as it cannot be ruled out that the rules of the game will change again on the part of the EU Commission and Google.

Make sure that your CSS partner does not charge high set-up costs

Additional services usually make sense

The use of CSS is only one aspect of optimizing shopping campaigns. For many online retailers, it can therefore make sense to take advantage of additional services such as feed optimization or the complete management of Google Shopping campaigns.

How does the switch to CSS work?

If you would like to use CSS via a Google CSS partner such as, they will submit an application to activate and connect your Merchant Center Account (MCA) with the selected partner. The underlying process controlled by Google is fast and reliable, so that a changeover is possible within a few working days. There is little change to the display of the product ads themselves: If Shopping ads are placed via a CSS partner, only the link under the ad changes to e.g. „From UnitedAds. By the way: According to our information, approx. 0.5% – 0.8% of users click on exactly this link.

How do I choose the right CSS partner?

Before you decide on a CSS partner, you should check whether it is a reputable or official provider that has ideally been established for a while.

There is nothing per se against smaller players in the market; however, make sure that you receive fast and effective support in the event of a problem. Therefore, find out about their services and notice periods from potential partners.

The price model and the costs incurred are also a relevant point: Does the portal charge additional CPCs or CPs (cost per sale)? Perhaps a monthly flat rate is also required?

Additional services such as the optimization of the Google Shopping campaign may also be relevant for you.