CSS for agencies: how to put all your clients' accounts on a partner CSS

For an agency managing Shopping campaigns, the CSS is the simplest improvement it can deliver to every client at once: same campaigns, same bids, up to 20% more power in the auction. This article explains how to do it at scale, which options you have and what to ask a CSS when you speak for 10, 50 or 200 accounts.

What the agency gains and what the client gains

• The client: the same budget buys more clicks, or the same clicks cost less. The effect shows in cost per conversion and ROAS, the metrics the agency is judged on.
• The agency: an improvement deliverable in the first week of a collaboration, without changing anything in the campaigns, plus a concrete argument when pitching ("we move you to a partner CSS from day one").
• Operational risk: zero. Activation is an approval in Merchant Center, campaigns do not stop, and the account stays the client's.

The three options for an agency

Option	How it works	For whom	Cost and effort
Self-service partner CSS (e.g. Bigconvert CSS)	Each client account is activated on the partner's CSS; the agency or the client pays the fee	Most agencies	Fee per store, with volume discounts; zero infrastructure
Your own CSS	The agency builds a price comparison site and gets it accredited by Google	Large agencies with hundreds of accounts	A working comparison site, at least 50 distinct stores per country, continuous maintenance, Google checks; months of work
White label	An existing CSS operated under the agency's brand	Agencies that want their brand on the label	Higher flat monthly fee; offered by few providers

Bigconvert has been through all three: we run our own CSSs (Bigconvert.com, Bigconvert, ProductXL.com) for our agency's clients and offer them self-service to any other agency. We know what an own CSS costs; below a few hundred accounts, it is not worth it.

How to activate 20 or 200 accounts

1. The list of accounts: the clients' Merchant Center IDs (and, if you use an MCA / advanced account, the parent ID).
2. Send the list to the CSS. With Bigconvert CSS, agencies email [email protected] with the list and get a volume offer; no need to fill in the website form for every store.
3. The CSS sends the requests from CSS Center, for all accounts at once.
4. Approval happens in each Merchant Center (by the agency, if it has admin rights, or by the client). For accounts under an MCA, approval can be done once at parent level.
5. Opt out of Google Shopping in each account once the partner CSS is active, so the saving is complete.

Who pays and how to invoice

Two models, both used by the agencies we work with:

• The agency pays and includes the CSS in its fee. One monthly invoice from the CSS to the agency for all accounts. Simple to manage; the client sees the CSS as part of the service.
• The client pays directly. Each store takes its own subscription; the agency only coordinates. Useful when the client wants to keep the CSS if it changes agency.

Whatever the model, ask the CSS for: a single invoice for all accounts (if the agency pays), invoices with the correct VAT for each country, and the possibility to add or remove accounts monthly without penalties.

What to ask a CSS when you have several accounts

• Volume pricing, falling with the number of accounts, and no per-country charge.
• Bulk activation and a direct contact (not a form) for new accounts.
• Fast support when a client asks "what is this label on my ads?"; the standard answer is in this article.
• No exclusivity and no fixed-term contract: if you lose a client, you remove it from the list next month.
• Every country where your clients have stores, in one subscription.

Bigconvert CSS for agencies: volume pricing, bulk activation, support in English and Romanian on WhatsApp and email, every country in the programme. Write to [email protected] with the number of accounts.