Switching CSS Step-by-Step: How to Switch Without Campaign Interruption

What actually happens when switching CSS

When you switch, it changes which Comparison Shopping Service your product data is submitted to Google Shopping through. This is an account-level assignment – not a data migration and not a new account.

What changes:

• The CSS assignment of your Merchant Center. From the moment of the switch, your account will submit to the auction via the new CSS.
• The click price. The CSS advantage applies as a percentage to the CPC and takes effect immediately for all target markets where you advertise.
• Your contacts. Support, invoicing, and customer service will now be handled by the new CSS.

What does not change:

• Your shop. No changes to the shop system, no new scripts, no tracking modifications.
• Your Merchant Center. The same account ID, the same feeds, the same product IDs.
• Your campaigns. Structure, budgets, bidding strategies, and assets remain unchanged.
• Your history. Conversion data and campaign history remain in the account.

Are campaigns, bidding strategies, and learning phases retained?

This is the question that decides whether to switch in practice – and the answer is refreshingly unspectacular: Yes. Your campaigns continue to run, Smart Bidding does not start a new learning phase, and you don't need to set up any new Performance Max or Shopping campaigns.

The reason lies in the separation of layers. Bidding strategies learn based on conversion data in your Google Ads account. This data remains untouched because the account stays identical. The CSS merely determines under which identifier your offers enter the auction.

What you might see in the first few days is a slight movement in CPC and impressions – and in the desired direction: For the same bid, your offer is purchased more cheaply, meaning the same budget covers more clicks. This is the expected effect, not a symptom of a problem.

Migration in 5 Steps

The process is always the same, whether you currently advertise directly via Google Shopping or are coming from another CSS provider.

Step 1: Inventory

Note your Merchant Center ID, which feeds are active, which target markets you advertise in, and which campaign types are running. If you are currently with another CSS, also check the notice period – the switch itself is independent of this, but the billing is not.

Step 2: Initiate the Switch

You register with the new CSS and provide your Merchant Center ID. We will handle the assignment – you don't need to interpret an invitation, duplicate any feeds, or pause any campaigns.

Step 3: Check Feed and Shipping Information

Before the switch, it's the best time to look at the basics: Are shipping costs and delivery times correctly set up for each target market? Are availabilities and prices accurate? These points determine visibility – regardless of the CSS, but particularly noticeable right after a switch.

Step 4: Switch and First Day Monitoring

The switch happens during live operation. On the first day, check three things: Are products still approved, are impressions running as on the previous day, and is the average CPC moving downwards? That's all it takes – interventions in bids or budgets are counterproductive now.

Step 5: Evaluation After Two to Four Weeks

Only after two to four weeks will you have a reliable basis for comparison. Compare CPC, clicks, and revenue with the same period before – not individual days, but full weeks including weekends.

Timeline: Who Does What, and How Long Does It Take?

In total, that's about two hours of work on your part. The rest is waiting time for the assignment and subsequent observation.

Checklist Before Switching

• Feed status: No major open disapprovals in Merchant Center that you could attribute to the switch.
• Shipping and delivery time: Separately specified per target market, not generally the same for all countries.
• Prices and availability: Feed and shop match, especially for ongoing promotions.
• Campaign structure: Documented how it looks today – as a reference for before-and-after comparison.
• Tracking: Conversion measurement works and has not been changed shortly before the switch.
• Contract status: Notice period and billing cycle clarified with the previous CSS provider.

Typical Mistakes When Switching

• Feed changes simultaneously with the switch. After that, it's impossible to tell which effect comes from where. Switch first, then optimize.
• Adjusting bids and budgets. If you tweak the bidding strategy in the same period, you overwrite the effect you actually wanted to measure.
• Running two setups in parallel. One product belongs to one CSS. Duplicate structures don't create double visibility, but confusion in evaluation.
• Evaluating after three days. Too short periods show weekday effects, not the result of the switch.
• Forgetting target markets. The advantage applies to all countries you advertise in – if you only check your home market, you only see half the effect.
• Leaving shipping information unchecked. The most common reason for weak Shopping results has nothing to do with the CSS.

What the Switch Brings

The effect is proportional and impacts the click price: for an identical bid, you buy the same click cheaper. The more expensive the competition in your category, the greater the absolute advantage – and the faster the monthly fee is recovered.

Calculated on a Shopping budget of 1,000 per month, a 20% advantage on the click price corresponds to around 200 more click volume for the same money – without a single change to campaigns or feed. With us, this costs £17 per month, with no setup fee and no minimum contract term, including all target markets.

For most shops, therefore, switching is less a strategic decision than a cleanup task: exchanging a layer that is already there, and seeing the difference in CPC from day one.

Frequent Questions About Switching CSS