How to switch to a partner CSS in Google Merchant Center, step by step

Switching to a CSS takes a few minutes and is done through an approval in Merchant Center. The exact steps, what you see in your account, how to check which CSS you use now, what to do with Google Shopping afterwards and how to go back if you want.

By Updated: 6 min read

The thing we hear most often from stores: "sounds good, but I am afraid of breaking something". Switching to a CSS does not touch your feed, campaigns or billing. It is an approval on one page in Merchant Center. Here are the steps exactly as they happen, including what to do before and after.

What you need first

  • Your Merchant Center ID: the number in the top right corner of Merchant Center. That is all the CSS needs; no passwords, no account access.
  • Admin access to Merchant Center, so you can approve the request. If your agency owns the account, the agency approves.
  • An active, non-suspended Merchant Center account. If the account is suspended, fix the suspension first; a CSS cannot lift it for you.

The steps, in order

  1. Sign up with the CSS. With Bigconvert CSS you fill in the form on css.bigconvert.com with your name, website, Merchant Center ID, email and phone, then pay the subscription through Stripe (card). It takes 2 minutes.
  2. The CSS sends the request from CSS Center. CSS Center is Google's platform where CSSs manage their merchants. From there the CSS initiates an "account switch", the request to place your account's ads.
  3. You get the notification in Merchant Center. It appears under the notifications bell and usually by email too, worded like "[CSS name] wants to show ads for your products" (exact wording depends on the interface version).
  4. You approve. Open the notification or go to Settings → Comparison Shopping Services and click "Approve" / "Accept". In the older interface the page was called "CSS" under "Settings" or "Linked accounts".
  5. Done. From that moment your ads are placed by the new CSS and the label "By [CSS name]" appears under them. It usually shows in Google results within minutes; rarely a few hours.

With Bigconvert CSS you also get access to a client portal after approval, where you see your subscription and invoices and can cancel any time.

Save up to 20% on every Google Shopping click

Bigconvert CSS: €18.99 per month per store, no commission, cancel anytime. Activation takes 5 minutes.

Activate Bigconvert CSS

How to check which CSS you use now

  • In Merchant Center → Settings → Comparison Shopping Services you see the CSSs linked to your account and which one is active.
  • Search Google for one of your products and look at the label under the price in the Shopping carousel: "By Google" means you use Google's CSS; "By [other name]" means you use that CSS.

What to do with Google Shopping after the switch

An account can be linked to several CSSs at the same time. After moving to a partner CSS you can leave Google Shopping (Google's CSS) active in Merchant Center or opt out of it.

Our recommendation: opt out of Google Shopping once the new CSS is active. If both stay active, part of your ads keep being placed through Google's CSS, with its ~20% margin retained, and your saving is only partial. The setting is on the same Comparison Shopping Services page and can be reversed any time.

What happens to your campaigns in the first week

  • They do not stop and do not "relearn". History, budgets and bidding strategies stay.
  • Average CPC may fall gradually, not overnight, especially with automated bidding: Google adjusts bids as it sees you winning the same positions with lower bids.
  • Compare properly: the 30 days after the switch against the 30 before, same campaigns, on cost per click, impression share and cost per conversion. Seasonality (Black Friday, holidays) can hide or exaggerate the effect.

How to go back or change CSS

Same page in Merchant Center. You can reactivate Google Shopping or approve another CSS's request at any time; the Merchant Center account is yours and no CSS can lock you in. With Bigconvert CSS the subscription is cancelled from the client portal, with no notice period.

Frequently asked questions

Do I have to give anyone access to Google Ads or Merchant Center?expand_more

No. A self-service CSS only needs your Merchant Center ID. You approve the request from your own account.

How long does the switch take?expand_more

Sign-up: 2 minutes. The request from CSS Center: usually the same working day (with Bigconvert CSS, within minutes during working hours). Your approval: one click. Ads show through the new CSS within minutes.

Can I use two CSSs at the same time?expand_more

Yes, Merchant Center allows several linked CSSs. For the full saving, opt out of Google's CSS once the partner CSS is active.

What if I do not approve the request?expand_more

Nothing: the account stays on its current CSS. The request expires and can be resent.

Save up to 20% on every Google Shopping click

Bigconvert CSS: €18.99 per month per store, no commission, cancel anytime. Activation takes 5 minutes.

Activate Bigconvert CSS

Read next

What is Google CSS and how does it lower your Google Shopping cost per click
A CSS (Comparison Shopping Service) is a price comparison service through which stores place their Google Shopping ads. Through a partner CSS, your whole bid enters the auction instead of about 80% of it. Here is where the difference comes from, what changes in your account and what it costs.
CSS and Performance Max: where the discount applies and where it does not
The CSS saving applies to the Shopping component of Performance Max, to standard Shopping campaigns and to Demand Gen with a product feed. It does not apply to Search, Display, YouTube or free listings. Each case explained, and how to measure the effect properly.
How much does a Google CSS cost: pricing models, public prices and when it pays off
A partner CSS costs between nothing and a few hundred euros a month depending on the model: flat fee, percentage of ad spend or bundled in an agency fee. Public prices of the main CSSs in Europe (October 2026) and a simple calculation to see from which budget it is worth it.